tag:theconversation.com,2011:/ca/topics/red-squirrels-19737/articlesRed Squirrels – The Conversation2024-02-21T13:04:38Ztag:theconversation.com,2011:article/2232242024-02-21T13:04:38Z2024-02-21T13:04:38ZGut bacteria may explain why grey squirrels outcompete reds – new research<p>Across large parts of the UK, the native red squirrel has been replaced by the grey squirrel, a North American species. As well as endangering reds, grey squirrels pose a threat to our woodlands because of the damage they cause to trees. </p>
<p><a href="https://www.microbiologyresearch.org/content/journal/jmm/10.1099/jmm.0.001793">New research</a> from my colleagues and I compared the gut bacteria of red and grey squirrels. We found that differences between the two may explain their competition and red squirrel decline, as well as why grey squirrels are so destructive to woodland.</p>
<p>Grey squirrels were introduced to the UK between 1876 and 1929 and have displaced reds in most areas of the UK. Greys carry a virus called “squirrelpox”, which doesn’t affect them but leads to sickness and often death in red squirrels.</p>
<p>Grey squirrels are bigger than red squirrels and compete with them <a href="https://www.frontiersin.org/articles/10.3389/fevo.2023.1083008/full">for food and habitat</a>.
Acorns, a widespread food source, contain tannins, which are hard for red squirrels to digest. But greys can digest acorns easily, giving them an extra edge in competing for resources. </p>
<p>Grey squirrels frequently strip the bark from deciduous trees. In commercial plantations, the damage can lead to fungal infection and result in the tree producing low quality timber. The annual cost is an <a href="https://rfs.org.uk/insights-publications/rfs-reports/report-overview-the-cost-of-grey-squirrel-damage-to-woodland-in-england-and-wales/">estimated £37 million.</a> with sycamore, oak, birch and beech frequently targeted. </p>
<p>The grey squirrels select the strongest growing trees as these have bark containing the largest volume of sap. Intriguingly, grey squirrels do not select trees with the <a href="https://www.researchgate.net/publication/230344319_Bark-stripping_by_Grey_squirrels_Sciurus_carolinensis">highest sugar content</a>. This observation has led scientists to posit that the squirrels consume bark to obtain <a href="https://www.sciencedirect.com/science/article/pii/S0378112716300421?via%3Dihub">certain micro-nutrients</a>. </p>
<h2>Gut bacteria</h2>
<p>All mammals have microorganisms living in their intestines. For example, the typical human colon is host to at least <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5847071/">160 bacterial species</a>, while in birds, research has found thousands of different bacterial species in <a href="https://pubmed.ncbi.nlm.nih.gov/33868800/">chicken intestines.</a></p>
<p>The bacteria break down foods and help synthesise vitamins, complementing the enzymes secreted by the body. The diversity of these microorganisms, known as the “microbiota”, can reflect the level of health and also the diet of an individual. But we don’t know enough about the microbiota living in squirrel intestines. </p>
<p>The types of microbes present vary between species, yet the extent to which they differ between grey and red squirrels is unclear. We explored this and investigated the potential for any differences to affect competition between the two squirrel species. We also examined whether gut bacteria might be playing a role in bark stripping behaviour.</p>
<p>We sampled bacterial DNA from red and grey squirrel intestinal contents and performed gene sequencing to identify the range of bacteria present in the samples. The results were analysed to compare any important differences between the two.</p>
<figure class="align-center ">
<img alt="A cute red squirrels with a large bushy tail stands on the branch of a tree." src="https://images.theconversation.com/files/576545/original/file-20240219-20-ivfdqj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576545/original/file-20240219-20-ivfdqj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=430&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576545/original/file-20240219-20-ivfdqj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=430&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576545/original/file-20240219-20-ivfdqj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=430&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576545/original/file-20240219-20-ivfdqj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=541&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576545/original/file-20240219-20-ivfdqj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=541&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576545/original/file-20240219-20-ivfdqj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=541&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Ynys Môn off the north Wales coast is one of the few places in the UK where greys have been eradicated in favour of red squirrels.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/red-squirrel-views-around-north-wales-2232607907">Gail Johnson/Shutterstock</a></span>
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<h2>Calcium</h2>
<p>Calcium is an important nutrient in the body and is required for healthy bones, muscles and nerves. It is especially needed by lactating animals and ones that are young and growing.</p>
<p>We found that grey squirrels may have the capacity to obtain the calcium that exists in tree bark thanks to the presence of a bacteria called “oxalobacter” in their gut. The calcium in tree bark comes in an insoluble form and is hard for an animal to digest. But oxalobacter would be able to change this into a form that could be more digestible. </p>
<p>Calcium levels <a href="https://www.sciencedirect.com/science/article/pii/S0378112716300421?via%3Dihub">increase in trees</a> as active growth resumes after winter dormancy. This happens immediately before the main squirrel bark-stripping season of May to July. Our research may therefore help to explain the destructive behaviour of grey squirrels and why red squirrels appear to strip bark much less frequently.</p>
<p>Our research also identified a significantly higher diversity of bacteria in the intestines of grey squirrels compared to red squirrels. This could hold the key to further understanding why grey squirrels outcompete red squirrels in the UK. </p>
<p>A more diverse range of bacteria being sustained in the gut means that grey squirrels potentially may be able to access a broader range of resources than red squirrels in addition to acorns.</p>
<h2>Adenovirus</h2>
<p>The grey squirrel harbours not just the squirrelpox virus, but also another potential threat – adenovirus. While this virus causes severe intestinal lesions in some red squirrels, curiously, grey squirrels never exhibit the same symptoms.</p>
<p>This discrepancy underscores the fascinating and complex potential role of gut microbiota. Research increasingly reveals their influence on everything from digestion to immune response, and even susceptibility to disease.</p>
<p>In the context of red squirrels, understanding how variations in their gut bacteria might predispose them to adenovirus becomes crucial. This is especially pertinent for captive breeding programs, where adenovirus infections pose a hurdle to successful reintroductions of red squirrels into the wild.</p>
<p>Given we only sampled red and grey squirrels from north Wales, we hope that future studies will map the gut microbiota of other European populations too. Such future research will continue to improve our knowledge of the competition between red and grey squirrels.</p><img src="https://counter.theconversation.com/content/223224/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Craig Shuttleworth does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>New research suggests the gut bacteria of red and grey squirrels differ significantly, potentially explaining the decline of the native red and the success of its grey counterpart.Craig Shuttleworth, Honorary Visiting Research Fellow, Bangor UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1940312023-02-27T17:22:54Z2023-02-27T17:22:54ZPlant and animal species that adapt quickly to city life are more likely to survive<figure><img src="https://images.theconversation.com/files/512056/original/file-20230223-2271-9vv3ym.jpg?ixlib=rb-1.1.0&rect=8%2C0%2C5982%2C3997&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A global study of urban clover reveals that it is adapting quickly to city life.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><iframe style="width: 100%; height: 100px; border: none; position: relative; z-index: 1;" allowtransparency="" allow="clipboard-read; clipboard-write" src="https://narrations.ad-auris.com/widget/the-conversation-canada/plant-and-animal-species-that-adapt-quickly-to-city-life-are-more-likely-to-survive" width="100%" height="400"></iframe>
<p>It’s five o'clock on a summer morning in Winnipeg. Our research team is unloading a series of small traps from the trunk of our car, which is parked on a residential road. Using a stick, we slather peanut butter from a huge jar into each trap as bait and quietly sneak into the yards we’ve been given permission to enter, placing the traps in suitable locations. </p>
<p>A dogwalker gives us a suspicious glance as they walk by. Traps now set and open, we wait. This effort is to investigate how animals respond to urbanization and <a href="https://doi.org/10.1002/ecs2.3918">what traits enable them to colonize and persist in cities</a>.</p>
<h2>Urban nature</h2>
<p>Urban ecology and evolution are still relatively new fields of study — for a long time, researchers preferred to study nature in remote locations farther away from human influence. But a growing number of scientists are now studying the <a href="https://doi.org/10.1126/science.aaf3630">ecology</a> and <a href="https://doi.org/10.1126/science.aam8327">evolution</a> of animals and plants found in our own backyards, reflecting a realization that cities are important ecosystems where plants, animals, humans and other organisms coexist. </p>
<p>Yet these cities are challenging places for wildlife and plants. Cities are <a href="https://doi.org/10.1002/joc.2201">hot</a>, <a href="https://theconversation.com/urban-noise-pollution-is-worst-in-poor-and-minority-neighborhoods-and-segregated-cities-81888">noisy</a> and <a href="https://theconversation.com/toxic-cities-urban-wildlife-affected-by-exposure-to-pollutants-127590">polluted</a>. The numerous buildings, cars, pets and, of course, people going about their business <a href="http://dx.doi.org/10.5751/ACE-00581-080211">pose many dangers</a> to the species that increasingly share our living quarters. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/512060/original/file-20230223-24-2iu9g0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="a red squirrel perched in an eavestrough" src="https://images.theconversation.com/files/512060/original/file-20230223-24-2iu9g0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/512060/original/file-20230223-24-2iu9g0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/512060/original/file-20230223-24-2iu9g0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/512060/original/file-20230223-24-2iu9g0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/512060/original/file-20230223-24-2iu9g0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/512060/original/file-20230223-24-2iu9g0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/512060/original/file-20230223-24-2iu9g0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Studying red squirrel populations in urban neighbourhoods can show how they have evolved different behaviours to adapt to city life.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
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</figure>
<p>The remaining natural vegetation is also altered in cities. For example, interest in <a href="https://doi.org/10.1016/j.landurbplan.2019.103730">gardening has introduced many new plants and trees to cities</a> that aren’t found in nearby natural areas. These complex and intertwining environmental modifications can make finding food, a suitable mate or a safe shelter challenging for most animals, and make it difficult for native species of plants to thrive in cities.</p>
<h2>What does it take to thrive?</h2>
<p>So, what enables some species to succeed in city living, where other species fail? One of the most important qualities in urban animals is their ability to change their behaviour, coming up with innovative ways to socialize, avoid dangers or cope with challenging urban environmental conditions. </p>
<p>For example, <a href="https://doi.org/10.1163/1568539X-bja10122">mountain chickadees that nest in cities are bolder than their rural counterparts</a> in Kamloops, B.C. Urban coyotes <a href="https://doi.org/10.1093/beheco/arv102">avoid humans (and particularly their cars) by being more active at night</a> in Edmonton. And <a href="https://doi.org/10.1098/rsbl.2020.0813">rosy-faced lovebirds use air-conditioning vents</a> to cool off on hot days in Phoenix, Ariz. </p>
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Read more:
<a href="https://theconversation.com/how-coyotes-and-humans-can-learn-to-coexist-in-cities-147738">How coyotes and humans can learn to coexist in cities</a>
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<p>We also see evidence of rapid evolution in cities, where the genetic material of a population is changing. Urban water fleas, for example, <a href="https://doi.org/10.1111/1365-2435.13184">grow and mature faster</a> and can <a href="https://doi.org/10.1111/gcb.13784">withstand higher temperatures</a> than rural water fleas. Anolis lizards in Puerto Rico have <a href="https://doi.org/10.1111/evo.12925">evolved longer limbs and more toe lamellae — fine scales on the bottom of their feet — in cities</a>, traits that may help individuals better cling to smooth urban surfaces like glass, metal or painted concrete.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/512059/original/file-20230223-16-cx42uf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="a brown lizard perched on a rusted rod" src="https://images.theconversation.com/files/512059/original/file-20230223-16-cx42uf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/512059/original/file-20230223-16-cx42uf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/512059/original/file-20230223-16-cx42uf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/512059/original/file-20230223-16-cx42uf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/512059/original/file-20230223-16-cx42uf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/512059/original/file-20230223-16-cx42uf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/512059/original/file-20230223-16-cx42uf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Anolis lizards living in urban areas in Puerto Rico have evolved longer limbs.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<h2>Urban clover</h2>
<p>Recently, researchers wanted to know just how widespread these kinds of rapid evolutionary changes are across our cities. <a href="https://www.globalurbanevolution.com/">A global team of researchers</a> — led by University of Toronto scientists and including team members from both my former University of Manitoba lab, and my <a href="https://www.concordia.ca/news/stories/2022/04/20/cities-are-driving-evolutionary-change-in-the-cosmopolitan-white-clover-a-new-global-study-finds.html">department at Concordia University</a> — teamed up to answer this question using the humble clover plant. </p>
<p>The Global Urban Evolution project (or GLUE) underscores <a href="https://knowablemagazine.org/article/living-world/2022/urban-evolution-species-adapt-survive-cities">the important role of cities as testbeds</a> to advance our understanding of the natural world, and evolutionary ecology in particular.</p>
<p>Clover is ubiquitous in cities across the world so researchers visited parks, lawns and roadsides to collect samples from 160 cities and surrounding areas on five continents (gathering a few more suspicious glances from dogwalkers along the way). Considered among “<a href="http://ikee.lib.auth.gr/record/300591?ln=en">the best replicated test of parallel evolution, on the largest scale ever attempted</a>,” results suggest clover populations are indeed <a href="https://doi.org/10.1126/science.abk0989">adapting to urban environments worldwide</a>. </p>
<p>As the GLUE project shows, research undertaken in cities <a href="https://doi.org/10.1016/j.tree.2022.07.012">can help us better understand basic ecological and evolutionary processes and mechanisms</a>. This knowledge can also help us protect declining species, which is critical as we face the dual challenges of biodiversity loss and climate change. </p>
<p>If urban species are evolving, and seemingly before our very eyes, that means <a href="https://urbanevolution-litc.com/2020/05/19/conserving-urban-biodiversity-needs-an-evolutionary-mindset/">biodiversity conservation and management goals are moving targets</a>. Understanding how species are changing over time can help us to better plan and manage for greener, more biodiverse cities. This, in turn, has important implications for the well-being of the 55 per cent of the world’s human population who call an urban area home.</p>
<h2>Studying an urbanizing world</h2>
<p>Back in Winnipeg, a trap in a nearby yard is rattling. A tiny red squirrel has found the peanut butter breakfast and is now full — and also stuck. It’s time for me to get to work. I weigh and measure the squirrel, and then mark it for future identification. Ultimately, this work will tell us how squirrels alter their activity in cities, for example by waking up earlier compared to squirrels in more natural areas, <a href="https://doi.org/10.1098/rspb.2013.0593">as has been found for urban birds</a>. </p>
<p>So, the next time you notice someone catching squirrels in your neighbourhood, collecting clover on lawns or water fleas in city ponds, you might just be witnessing an urban evolutionary ecologist hard at work, trying to discover just what makes their favourite species successful at city living.</p><img src="https://counter.theconversation.com/content/194031/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Riikka Kinnunen's PhD work was supported by a Natural Sciences and Engineering Research Council of Canada Discovery Grant and the University of Manitoba Graduate Fellowship and University of Manitoba Graduate Enhancement of Tri-Council Stipends funding grant. </span></em></p><p class="fine-print"><em><span>Carly Ziter receives funding from the Natural Sciences and Engineering Research Council of Canada, The Social Sciences and Humanities Research Council of Canada, The Fonds de recherche du Québec – Nature et technologies, and Concordia University</span></em></p>Animals and plants living in cities are more likely to thrive when they are able to quickly adapt to urban conditions.Riikka Kinnunen, Postdoctoral research fellow, Biology, Concordia UniversityCarly Ziter, Associate professor, Biology, Concordia UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1968112022-12-21T17:08:14Z2022-12-21T17:08:14ZSquirrelpox outbreak detected in north Wales – without a vaccine, the disease will keep decimating red squirrels<p>Concerns over the spread of squirrelpox have increased after a <a href="https://www.bbc.co.uk/news/uk-wales-63865940">sick red squirrel was found in Bangor, Wales, in late November</a>. </p>
<p>It’s not the first time an outbreak has happened in the area – back in 2020/21, the disease caused a loss of <a href="https://www.mdpi.com/2076-2615/12/1/99">70%-80% of its red squirrel population</a>. Such major outbreaks are devastating and lead to <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/ece3.1216">dramatic and ongoing red squirrel declines</a>.</p>
<p>Conservationists have a formidable task to ensure that similar losses do not happen again. The current national strategy is simple: <a href="https://www.gov.wales/grey-squirrel-management-action-plan-for-wales">cull grey squirrels</a> in areas where red squirrels persist. However, there is no single, straightforward way to safeguard the future of this native mammal at the moment.</p>
<p>It is the grey squirrel which <a href="https://zslpublications.onlinelibrary.wiley.com/doi/10.1111/j.1469-1795.2000.tb00107.x">carries squirrelpox virus infection</a>, but it does not cause them obvious harm. When they were first introduced from North America during the Victorian era, <a href="http://www.italian-journal-of-mammalogy.it/pdf-126011-61760?filename=Introduced%20Canadian.pdf">grey squirrels brought the virus to Britain</a> and Ireland. </p>
<p>Grey squirrels compete for resources with <a href="https://www.bbc.co.uk/programmes/p0cc7l69">native red squirrels</a>, which is a species with <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1690913/pdf/11886647.pdf">little immunity to the virus</a>. The infection produces extensive skin lesions around the eyes, muzzle and mouth, on the digits and around the genitalia. The sores become infected by bacteria and are a major source of viral particles which contaminate the environment. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/502171/original/file-20221220-17-dycnm8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/502171/original/file-20221220-17-dycnm8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/502171/original/file-20221220-17-dycnm8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/502171/original/file-20221220-17-dycnm8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/502171/original/file-20221220-17-dycnm8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/502171/original/file-20221220-17-dycnm8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/502171/original/file-20221220-17-dycnm8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Red squirrel with squirrelpox virus.</span>
<span class="attribution"><a class="source" href="https://flickr.com/photos/55426027@N03/14469405549">Peter Trimming / Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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<p>This increases the likelihood of sick red squirrels spreading infection to other reds. Squirrelpox leads to <a href="https://www.cambridge.org/core/journals/epidemiology-and-infection/article/epidemics-of-squirrelpox-virus-disease-in-red-squirrels-sciurus-vulgaris-temporal-and-serological-findings/6543EE3ED2792F0C9CD188EE3973EED8">death within three weeks</a> of infection. </p>
<h2>Does culling work?</h2>
<p>On the island of Anglesey, off the northern coast of Wales, culling between 1998 and 2013 led to the <a href="https://www.independent.co.uk/climate-change/news/the-uk-island-which-has-completely-wiped-out-grey-squirrels-a6708781.html">eradication of grey squirrels</a>. As those efforts steadily reduced grey squirrel numbers, the proportion of remaining greys exposed to squirrelpox virus and showing <a href="https://link.springer.com/article/10.1007/s10530-014-0671-8">antibodies progressively dwindled</a> to zero, revealing that the virus eventually disappeared from their population.</p>
<p>With fewer hosts to infect, eventually the infection was simply unable to spread between hosts. Although red squirrels were reintroduced before the grey squirrel eradication was completed, the steady decline in levels of infection among grey squirrels explains why no diseased reds were found on the island.</p>
<p>Across Wales, an <a href="https://research.bangor.ac.uk/portal/en/researchoutputs/striving-for-success-an-evaluation-of-local-action-to-conserve-red-squirrels-sciurus-vulgaris-in-wales(1963b515-5120-482d-b11b-59da05c9457a).html">estimated 1,500 red squirrels</a> may remain. Whereas there were only <a href="https://cdn.naturalresources.wales/media/691092/eng-red-squirrel-conservation-plan-for-wales.pdf">40 on Anglesey in 1998</a>, today there are perhaps 800. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1597980163266195456"}"></div></p>
<p>In 2009, red squirrels were first recorded on the Gwynedd mainland having <a href="https://www.dailypost.co.uk/news/north-wales-news/red-squirrels-spotted-areas-first-13519515">crossed the narrow Menai Strait from Anglesey</a>. This population expanded but since 2017, there have been repeated <a href="https://www.bbc.co.uk/news/uk-wales-north-west-wales-42377351">squirrelpox outbreaks</a> there. </p>
<p>The problem with culling outside of a closed environment like an island is that, to be effective, control has to be coordinated over ever-larger areas, which is expensive and time-consuming. Sporadic or localised mainland grey squirrel culling simply leads to <a href="https://www.jstor.org/stable/20728617">rapid re-invasion</a>. </p>
<p>Red squirrels also naturally return to the habitats from where greys are removed. This inevitably leads to mixing and continued risk of infection.</p>
<h2>Birth control</h2>
<p>So what more can be done? A complementary, non-lethal population control method is being developed. This is an oral <a href="https://theconversation.com/grey-squirrels-is-birth-control-the-solution-to-britains-invasive-species-problem-154400">contraceptive bait</a> which, if consumed, makes grey squirrels infertile. It would be deployed in hoppers designed to only allow grey squirrels access.</p>
<p>Although this is an exciting prospect, research suggests effective use would <a href="https://www.sciencedirect.com/science/article/abs/pii/S0304380020304506">require grey populations to be reduced first by culling</a>, before the contraceptive is presented. Using bait will also require coordination between a multitude of landowners, not all of whom may wish to be involved or pay for control.</p>
<p>It is therefore an important part of a future solution, but not a simple panacea. </p>
<h2>Pine marten to the rescue?</h2>
<p>Another interesting possibility could be to use pine martens to control the grey population. The pine marten is being reintroduced into many parts of Britain <a href="https://linkinghub.elsevier.com/retrieve/pii/S2352249620300240">including woodlands adjacent to Anglesey</a>. The occasional individual has been <a href="https://www.dailypost.co.uk/news/north-wales-news/rare-squirrel-eating-predator-discovered-24466313">detected on the island</a> too. </p>
<p>Pine marten <a href="https://theconversation.com/grey-squirrels-are-oblivious-to-threat-from-pine-martens-giving-native-reds-the-advantage-131064">predation is more pronounced upon grey</a> than red squirrels, and this fact could lead to the suppression of the squirrelpox pathogen. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/502129/original/file-20221220-20-w0zd44.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/502129/original/file-20221220-20-w0zd44.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=352&fit=crop&dpr=1 600w, https://images.theconversation.com/files/502129/original/file-20221220-20-w0zd44.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=352&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/502129/original/file-20221220-20-w0zd44.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=352&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/502129/original/file-20221220-20-w0zd44.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=443&fit=crop&dpr=1 754w, https://images.theconversation.com/files/502129/original/file-20221220-20-w0zd44.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=443&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/502129/original/file-20221220-20-w0zd44.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=443&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The pine marten is being reintroduced into many parts of Britain.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>Recent <a href="https://www.sciencedirect.com/science/article/pii/S0304380022003143">mathematical modelling</a> has reinforced the potential role for this native predator in reducing the impact of invasive grey squirrels and the infectious diseases they harbour. <a href="https://linkinghub.elsevier.com/retrieve/pii/S2352249620300240">Research by myself and colleagues</a> suggests that grey squirrels would decline if pine martens are reintroduced, and often their numbers would then be insufficient for the virus to be maintained. </p>
<p>One uncertainty is exactly how much of an effect this predator would have, because it is omnivorous and hunts a wide variety of prey. When vole populations are high, for example, pine martens may focus their hunting on this prey, and <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/oik.08565">less on grey or red squirrels</a>. Nevertheless, pine marten recovery is likely to be a positive contribution to grey squirrel management and our modelling predictions are dramatic. </p>
<p>Unfortunately, both this and commercial contraceptive use are only likely to assist in the medium to long term. Consequently, we are currently left with expensive ongoing local culling programmes. </p>
<h2>A vaccine is essential</h2>
<p>A big gap in our ability to fight squirrelpox comes from the fact there is currently <a href="https://squirrelaccord.uk/squirrels/squirrel-pox-disease/">no vaccine available for the disease</a>. The <a href="https://www.wildlifearktrust.com/appeal.html">Wildlife Ark Trust</a> funded a vaccine development programme, but insufficient funding meant this research stopped a decade ago.</p>
<p>With no way to inoculate red squirrels against the pox virus, we can do little in the face of inevitable future squirrelpox outbreaks such as that which occurred near Bangor. It is to our collective shame that research halted because of insufficient funding and political will.</p><img src="https://counter.theconversation.com/content/196811/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>I have given long standing and public support for the Wildlife Ark Trust vaccine appeal. </span></em></p>There is no single, straightforward way to safeguard the future of this native mammal at the moment – but here are some optionsCraig Shuttleworth, Honorary Visiting Research Fellow, Bangor UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1615392021-06-23T17:00:45Z2021-06-23T17:00:45ZWe eavesdropped on some Canadian lynx: What we heard was surprising<figure><img src="https://images.theconversation.com/files/407717/original/file-20210622-23-1xppc82.jpg?ixlib=rb-1.1.0&rect=0%2C34%2C3264%2C2135&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The secret lives of lynx are revealed through audio recordings.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>Wildlife ecologists study what drives animal behaviour, and trying to figure it out is tricky. Not only are ecosystems incredibly complex, behaviours are driven by various <a href="https://doi.org/10.1016/j.tree.2014.11.004">internal and external factors</a> and the simple observation of behaviour is an eternal problem. </p>
<p>As wildlife ecologists, we know that when we observe wildlife, we cannot know what effect our presence has on the behaviour of our subject — not to mention the difficulties of observing animals in the wild, including those which roam across vast forested landscapes. So we must resort to sneakier ways.</p>
<p>In <a href="https://doi.org/10.1111/2041-210X.13605">a recently published research study</a>, we unlocked a new and effective way to monitor the behaviour of one of the most elusive predators in the boreal forest: the Canada lynx. Although <a href="https://doi.org/10.2307/3802461">GPS tracking of wildlife is not new</a>, it is typically only used to monitor movement behaviour of wildlife. </p>
<p>In our case, we wanted to delve deeper into the secret lives of this mysterious cat and record their soundscapes. After multiple failed attempts and some clever solutions, we figured out how to safely attach a small microphone to our lynx collars — and it opened a whole new world.</p>
<h2>Effective audio recordings</h2>
<p>Much to our excitement, these recorders were very effective at <a href="https://www.cbc.ca/radio/quirks/may-8-sounds-of-a-predator-horses-are-well-diggers-grass-defuses-a-toxic-explosive-and-more-1.6016777/purring-fighting-chaos-and-crunching-bones-these-are-the-sounds-of-the-canada-lynx-1.6016797">capturing the behaviour of the lynx</a>: “cats being cats” (grooming, sleeping); social behaviour (aggressive interactions, purring, long-distance social calls); and hunting behaviour (chases, kills, feeding). </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/407808/original/file-20210623-20-1b4z27d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="a lynx without its mouth wide open" src="https://images.theconversation.com/files/407808/original/file-20210623-20-1b4z27d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/407808/original/file-20210623-20-1b4z27d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=411&fit=crop&dpr=1 600w, https://images.theconversation.com/files/407808/original/file-20210623-20-1b4z27d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=411&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/407808/original/file-20210623-20-1b4z27d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=411&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/407808/original/file-20210623-20-1b4z27d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=516&fit=crop&dpr=1 754w, https://images.theconversation.com/files/407808/original/file-20210623-20-1b4z27d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=516&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/407808/original/file-20210623-20-1b4z27d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=516&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Recording and analyzing the sounds of lynx revealed new information about their behaviour.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>Over the five years of our study in the Yukon’s Kluane region, we collected over 14,000 hours of audio recordings from 26 individual lynx. After using various methods of data processing, we were able to identify kills by Canada lynx with 87 per cent accuracy — an impressive feat. </p>
<p>Previously, to know that a single kill had been made often required a full day of intensive snowshoeing and tracking during the short winter days in the Yukon. But by recording multiple lynx, we could collect information 24 hours a day, while we warmed our feet by a wood stove in a rustic cabin. </p>
<p>In addition to audio recorders, we also attached accelerometers – small devices that measure activity over time like you would find in a FitBit. Together with GPS tracking devices, these “<a href="http://dx.doi.org/10.3354/esr00269">biologging technologies</a>” provide unprecedented insight into the complex behaviours of these cats.</p>
<h2>Lynx and hares</h2>
<p>Of particular interest to us is hunting behaviour.</p>
<p>Canada lynx and the snowshoe hare populations follow a cycle of population booms and busts. When hare populations are high, lynx have lots to eat — but then the high numbers of lynx cause hare populations to crash, consequently leading to a crash in lynx populations. When hares are preyed on less due to lower lynx numbers, the population increases again, thus <a href="https://doi.org/10.1111/1365-2656.12720">re-starting the cycle</a>. This all occurs over a period of about eight to 10 years. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/407809/original/file-20210623-19-1wp5pfg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="a lynx kitten" src="https://images.theconversation.com/files/407809/original/file-20210623-19-1wp5pfg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/407809/original/file-20210623-19-1wp5pfg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/407809/original/file-20210623-19-1wp5pfg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/407809/original/file-20210623-19-1wp5pfg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/407809/original/file-20210623-19-1wp5pfg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/407809/original/file-20210623-19-1wp5pfg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/407809/original/file-20210623-19-1wp5pfg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Lynx populations are affected by their food supply, but the hunters are more skillful at adapting than previously thought.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>But the story may be more complex: lynx switch to alternate prey — like <a href="https://doi.org/10.2307/3546927">red squirrels</a> — when hares are not available. Our custom-built collars are helping to understand when this switch may happen, as well as whether individual lynx respond differently to declining numbers of snowshoe hare.</p>
<p>Intriguingly, we also noticed much more social behaviour than we originally expected. Lynx are known as solitary animals that live and hunt on their own for most of the year. But many of our collared lynx, especially adult females, appeared to interact extensively with each other in groups of two to three: sleeping, grooming, travelling and even hunting side-by-side. </p>
<p>Although our collars revealed this surprisingly social behaviour, it seems that lynx don’t share food: after a kill, we would often hear lots of growling and snarling as if to ward off feeding attempts by other lynx. So, does this social behaviour influence their ability to find and kill prey? This is one of the many new questions we have about lynx behaviour as we continue to delve into the lives of these amazing boreal predators.</p><img src="https://counter.theconversation.com/content/161539/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rachael Derbyshire receives funding from the NSERC Canadian Graduate Scholarship fund, the Northern Scientific Training Program, and the Wildlife Conservation Society Canada's W. Garfield Weston Foundation Fellowship in Northern Conservation.
This research was not possible without permission from Champagne and Aishihik First Nation and Kluane First Nation complete this work within their traditional territories, and the support of the Yukon Government.</span></em></p><p class="fine-print"><em><span>For the research herein, Allyson Menzies received funding from Natural Sciences and Engineering Research Council (NSERC; Vanier Scholarships Program and CREATE program), the W. Garfield Weston Foundation, the Wildlife Conservation Society, and the Northern Scientific Training Program. Permission was granted by the Champagne and Aishihik First Nation to conduct research within their homeland in the Yukon Territory. Allyson currently works in partnership with the University of Guelph and Nature United. </span></em></p><p class="fine-print"><em><span>Emily Studd receives funding from Natural Sciences and Engineering Research Council (NSERC), the W. Garfield Weston Foundation, and the Northern Scientific Training Program. Permission was granted by the Champagne and Aishihik First Nation to conduct research within their homeland in the Yukon Territory. For this research, Emily was affiliated with McGill University and the University of Alberta. </span></em></p>Audio recordings of the secret lives of the Canada lynx demonstrate the value of technology in monitoring wildlife.Rachael Derbyshire, PhD candidate, Ecology, Trent UniversityAllyson Menzies, Postdoctoral Fellow, Wildlife Biology, University of GuelphEmily Studd, Postdoctoral Research Fellow, Wildlife Ecology, University of AlbertaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1522102021-03-25T14:30:40Z2021-03-25T14:30:40ZRed squirrels, socially distant by nature, teach us the value of good neighbours<figure><img src="https://images.theconversation.com/files/391501/original/file-20210324-13-1ytcuiv.jpg?ixlib=rb-1.1.0&rect=41%2C25%2C5535%2C3687&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Red squirrels benefit from long-term social relationships with their neighbours — from a distance.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>In the far reaches of Canada’s North, there’s a different type of social distancing happening this year. Amid the lingering snowdrifts and bowed branches of spruce trees, a small mammal yells a ferocious “stay away!” call that can be heard more than 100 metres away. </p>
<p>These “rattle” calls are made by a species abundant in the boreal forest — the North American red squirrel — and send a clear message to other neighbouring squirrels: “This is my territory. Stay off.”</p>
<p>Despite being small in stature, red squirrels are known for their ferocity. Both males and females occupy individual territories with a cache of food resources at the centre called a midden. These food resources are critical for red squirrels to survive the long cold Yukon winters and are defended vigorously. Red squirrels do not tolerate other individuals on their territories and rarely come into contact with their neighbours. </p>
<p>They are, in other words, the boreal experts on social distancing.</p>
<figure class="align-center ">
<img alt="a squirrel on a branch screaming" src="https://images.theconversation.com/files/381541/original/file-20210131-19850-1i8m4q7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/381541/original/file-20210131-19850-1i8m4q7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/381541/original/file-20210131-19850-1i8m4q7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/381541/original/file-20210131-19850-1i8m4q7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/381541/original/file-20210131-19850-1i8m4q7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/381541/original/file-20210131-19850-1i8m4q7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/381541/original/file-20210131-19850-1i8m4q7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A male red squirrel lets out a territorial call — called a rattle — at his neighbours.</span>
<span class="attribution"><span class="source">(Ryan Taylor)</span></span>
</figcaption>
</figure>
<p><audio preload="metadata" controls="controls" data-duration="4" data-image="" data-title="Red squirrel rattle" data-size="173299" data-source="(Erin Siracusa)" data-source-url="" data-license="" data-license-url="">
<source src="https://cdn.theconversation.com/audio/2113/rattle1.mp3" type="audio/mpeg">
</audio>
<div class="audio-player-caption">
Red squirrel rattle.
<span class="attribution"><span class="source">(Erin Siracusa)</span><span class="download"><span>169 KB</span> <a target="_blank" href="https://cdn.theconversation.com/audio/2113/rattle1.mp3">(download)</a></span></span>
</div></p>
<h2>Solitary, but not anti-social</h2>
<p>But despite being the loners of the North, our recent research shows that red squirrels, although they live most of their lives in isolation, <a href="https://doi.org/10.1016/j.cub.2020.10.072">maintain important relationships with their neighbours that have benefits for survival and reproductive success</a>. </p>
<p>The value of social relationships for humans and other group living mammals is well-established. As science journalist Lydia Denworth’s recent book <a href="https://lydiadenworth.com/books/friendship/"><em>Friendship</em></a> makes clear, maintaining these stable social bonds with others has tangible benefits for our health and can even enhance our lifespan.</p>
<p>But what about for a solitary, territorial species that spends most of its life living on an exclusive territory with little physical contact with other squirrels? Could social relationships still matter for a species such as this? We thought they could.</p>
<p>We recognized that while red squirrels rarely physically interact with each other, they regularly communicate and interact through their rattles. In this way, red squirrels engage in recurring interactions with squirrels that live close to them, facilitating the formation of social relationships that might matter for their survival and reproductive success.</p>
<h2>Decades of data</h2>
<p>Using 22 years of data collected as part of the <a href="https://redsquirrel.biology.ualberta.ca/people/graduate-students/">Kluane Red Squirrel Project</a>, a collaborative research initiative run by researchers from Canada and the United States, we set out to explore whether living near relatives or living near familiar individuals (those with whom a squirrel shared a long-term social relationship) could have benefits for red squirrels.</p>
<p>By individually marking red squirrels with unique ear tags and following them throughout their lives, we could keep track of key information like where they lived, how many babies they had each year and how long they survived. </p>
<p>This provided a detailed picture of the animal’s social environment, including whether they were related to their neighbours and how long they lived next to them. We could then ask how these different relationships with neighbours influenced survival and reproductive success. </p>
<p>What we found was surprising.</p>
<h2>Friends or family?</h2>
<p>Living near family, we thought, might provide important benefits, as kin share genes and therefore should be more likely to co-operate with one another. Indeed, previous research has shown that red squirrels might help relatives by <a href="https://doi.org/10.1007/s00265-013-1499-4">nest-sharing</a> in the coldest months or <a href="https://doi.org/10.1038/ncomms1022">adopting orphaned kin</a>. But despite our initial expectations, we found no benefits of living near kin.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/381559/original/file-20210201-23-qsgm9n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Four squirrel pups" src="https://images.theconversation.com/files/381559/original/file-20210201-23-qsgm9n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/381559/original/file-20210201-23-qsgm9n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/381559/original/file-20210201-23-qsgm9n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/381559/original/file-20210201-23-qsgm9n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/381559/original/file-20210201-23-qsgm9n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/381559/original/file-20210201-23-qsgm9n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/381559/original/file-20210201-23-qsgm9n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">25-day old red squirrel pups.</span>
<span class="attribution"><span class="source">(Erin Siracusa)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Instead, we found that having familiar neighbours (individuals that a squirrel has lived next to for a long time) had substantial benefits for both a red squirrel’s chances of survival and the number of babies they were able to produce each year. Having these long-term stable social relationships mattered, even for an apparently solitary species. </p>
<p>Why might this be? Think about it this way. </p>
<p>Imagine you just moved into a new house. You don’t know your neighbours and so might not trust them. You’re probably going to be cautious about locking your doors at night or making sure your security cameras are on when you go away for holiday. But the longer you live next to these same neighbours, the more you get to know and trust them. You recognize that your neighbours are not going to break into your house or steal from you, and so you can relax your defences.</p>
<p>The same thing happens for squirrels. When squirrels live next to one another year after year they develop bonds of familiarity. These long-term neighbours enter into a gentleman’s agreement — they are less likely to <a href="https://doi.org/10.1016/j.anbehav.2017.08.024">pilfer from each other</a> or fight about territory boundaries, which allows them to <a href="https://www.sciencedirect.com/science/article/abs/pii/S0003347219300673">reduce the time and energy spent defending their property</a>. This is a well-established phenomenon in territorial species called the “<a href="http://doi.org/10.1093/beheco/ary010">dear-enemy effect</a>.”</p>
<h2>Social arrangements into old age</h2>
<p>What was particularly surprising to us was how important these long-term social relationships were for squirrels in their later years. For older red squirrels, maintaining familiar neighbours could offset the declines in survival and reproductive success associated with ageing. </p>
<p>While growing a year older might normally result in a decline in a squirrel’s chances of survival, those chances would actually increase with age if their neighbours remained the same.</p>
<p>In theory, this could lead to the evolution of longer lifespans, but while we don’t see evidence of this phenomenon in red squirrels, it raises an interesting question about the role that social relationships might play in the aging process. As we continue to search for solutions to living longer, healthier lives, <a href="http://doi.org/10.1126/science.aax9553">accumulating evidence</a> seems to point toward social relationships as being the anti-aging solution we’ve all been looking for.</p>
<figure class="align-center ">
<img alt="researcher weighs a squirrel" src="https://images.theconversation.com/files/381560/original/file-20210201-21-1ciyu50.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/381560/original/file-20210201-21-1ciyu50.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/381560/original/file-20210201-21-1ciyu50.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/381560/original/file-20210201-21-1ciyu50.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/381560/original/file-20210201-21-1ciyu50.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/381560/original/file-20210201-21-1ciyu50.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/381560/original/file-20210201-21-1ciyu50.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Female red squirrels are weighed to assess their reproductive status as part of the Kluane Red Squirrel Project.</span>
<span class="attribution"><span class="source">(Erin Siracusa)</span></span>
</figcaption>
</figure>
<h2>The devil you know</h2>
<p>But while these long-term relationships among red squirrels certainly do not constitute friendships as we think of them, our findings open up an interesting possibility that squirrels might actually help one another. </p>
<p>Given how important familiar neighbours are to reproductive success and survival, red squirrels could benefit from keeping their adversaries alive. So against all evidence to the contrary, red squirrels might co-operate with their competitors, because if you’re a red squirrel, it’s better the devil you know than the devil you don’t. We don’t know what this co-operation looks like yet, but it’s an interesting avenue for future research. </p>
<p>So as we continue to take physical distancing and social isolation measures, it’s worth remembering that red squirrels build and benefit from long-term social relationships with their neighbours — from a distance. </p>
<p>Even in the midst of a pandemic, we don’t need to be in physical contact with one another to benefit from our social bonds.</p><img src="https://counter.theconversation.com/content/152210/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Erin Siracusa receives funding from the American Society of Mammalogists, the Arctic Institute of North America, the Natural Sciences and Engineering Research Council of Canada, and the National Institute of Health. </span></em></p>Red squirrels are solitary by nature, but research has found that they benefit from familiarity with other squirrels.Erin Siracusa, Postdoctoral Research Associate, Behavioural Ecology, University of ExeterLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1544002021-02-03T14:21:34Z2021-02-03T14:21:34ZGrey squirrels: is birth control the solution to Britain’s invasive species problem?<figure><img src="https://images.theconversation.com/files/382224/original/file-20210203-21-kb8tu8.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4020%2C2832&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/grey-squirrel-feeding-on-chestnuts-autumn-118390966">Scooperdigital/Shutterstock</a></span></figcaption></figure><p>There are thought to be 2.7 million grey squirrels in the UK, versus only 287,000 <a href="http://publications.naturalengland.org.uk/publication/5636785878597632">red squirrels</a>. The invasive greys, brought to Britain and Ireland from North America in the 1870s, are blamed for the disappearance of the native red throughout much of England and Wales, due to the squirrel pox virus they transmit and the fact that they compete for food and habitat with their smaller relatives.</p>
<p>As with the UK’s other invasive species, such as rabbits, signal crayfish and Japanese knotweed, introducing the grey squirrel has proved to be an expensive mistake. Not only do grey squirrels displace red squirrels, they strip bark from trees. <a href="https://rfs.org.uk/news/2020/1-2021/grey-squirrels-threatening-our-woodlands-to-tune-of-11bn/">A recent report</a> estimated that this could cost commercial forestry and native woodlands £1.1 billion (US$1.5 billion) over the next 40 years, including revenue lost to damaged timber, reduced carbon storage, tree replacement costs and squirrel control.</p>
<p>Despite efforts to kill grey squirrels over several decades, their populations remain large and widespread. So could <a href="https://www.bbc.co.uk/news/science-environment-55817385">government-backed plans</a> for using oral contraceptives to control their breeding be the turning point?</p>
<h2>Squirrel birth control</h2>
<p>Before we consider that question, let’s interrogate the idea that grey squirrels are bad for the environment because they damage trees. If we’re worried about carbon in the atmosphere then phasing out fossil fuels, not killing squirrels, is the top priority. And squirrels, even non-native greys, play an important role in woodlands by <a href="https://www.frontiersin.org/articles/10.3389/fevo.2020.00259/full">burying the nuts they find</a> and seeding new trees. If grey squirrels were to vanish overnight, then the natural regeneration of UK woodlands would probably slow.</p>
<p>Whether or not the damage caused by this invasive species is exaggerated, these reports inevitably encourage calls for bigger <a href="https://www.telegraph.co.uk/news/2021/01/21/royal-forestry-society-urges-grey-squirrel-cull-wake-1bn-woodland/">culls of grey squirrels</a>. Oral contraceptives might at least be a more humane alternative to live trapping and bludgeoning the animals to death.</p>
<p>Birth control has worked for keeping wildlife populations elsewhere in check. The method, which often involves injecting contraceptives, has proved successful in more than 85 species, including wild horses and elephants, according to <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/j.1600-0897.2011.01003.x">a 2011 review</a>. Contraceptives halved dense and destructive populations of North American <a href="https://pdfs.semanticscholar.org/7383/a4c2227392c16c8c6269fd3e91fa65c728a4.pdf?_ga=2.143665589.1480929846.1612138237-212678758.1612138237">white-tailed deer</a> in under 10 years.</p>
<p>Research into using oral contraceptives on grey squirrels in the UK has been ongoing for <a href="https://squirrelaccord.uk/squirrels/fertility_control/">several years</a>, and recent results show promise. Trials using feeders that only grey squirrels can access, baited with hazelnut spread laced with an <a href="https://www.humanesociety.org/resources/questions-and-answers-about-immunocontraception">immunocontraceptive</a> (a drug which tricks the body’s immune system into producing antibodies that interfere with reproduction, by blocking the sperm receptor sites on eggs, for example) indicate that <a href="https://squirrelaccord.uk/news/blog/fertility-research-news-from-the-field/">around 90%</a> of a local population can be treated using this method. Researchers hope this could induce infertility to such an extent that treated populations shrink substantially over time.</p>
<p>Contraceptives have their own <a href="https://conbio.onlinelibrary.wiley.com/doi/full/10.1111/csp2.171">ethical concerns</a> though. Being alive isn’t necessarily always better than being dead. We don’t really know what physiological and psychological effects an inability to breed will have on the welfare of grey squirrels.</p>
<p>It’s also important that this contraceptive doesn’t affect other species, though there are measures to ensure this. Bespoke feeding boxes that only grey squirrels can enter limit the risk to other species, in particular red squirrels, by weighting the door of the feeder so that the smaller red <a href="https://squirrelaccord.uk/news/blog/fertility-research-news-from-the-field/">cannot enter</a>. Providing the bait in a hazelnut spread, rather than nuts which squirrels may bury, prevents other animals inadvertently finding and eating the contraceptive. But what about predators? Will their fertility be threatened by eating prey dosed with contraceptives?</p>
<h2>The alternatives</h2>
<p>There are other ways to control grey squirrel populations, such as <a href="https://thebiologist.rsb.org.uk/biologist/158-biologist/features/2245-accelerating-evolution">gene drives</a>. These are altered genes that can be implanted in males and programmed to induce infertility in the genome of their female offspring. Female infertility spreads through the population as the gene drive is carried and inherited by males. Gene drives don’t carry the same risk of cross-contamination between species that contraceptives do, and they are cheaper and easier to implement.</p>
<p>But they still have a long way to go before they’re approved as a control method, as scientists worry that a gene drive could spread from invasive to native populations. Imagine a grey squirrel in the UK that had been treated with a gene drive somehow made it back into their native range in North America – it could mean their extinction.</p>
<p>Perhaps the most popular solution to the grey problem is the pine marten, a predatory mammal that is slightly larger than a ferret. Almost hunted to extinction in the UK, pine martens have made a comeback in recent years. <a href="https://royalsocietypublishing.org/doi/pdf/10.1098/rspb.2017.2603">Research suggests</a> that where martens return to woodland they reduce grey squirrel populations, while boosting the number of red squirrels. But pine martens aren’t going to colonise the entire country – and they are still predators which eat other wildlife and some domestic animals. Their return is likely to face <a href="https://www.scotlandbigpicture.com/rewilding-stories/the-return-of-the-taghan">resistance in some places</a>.</p>
<figure class="align-center ">
<img alt="A weasel-like mammal hugging a river bank to sip the water." src="https://images.theconversation.com/files/381704/original/file-20210201-19-1s9s592.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/381704/original/file-20210201-19-1s9s592.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=413&fit=crop&dpr=1 600w, https://images.theconversation.com/files/381704/original/file-20210201-19-1s9s592.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=413&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/381704/original/file-20210201-19-1s9s592.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=413&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/381704/original/file-20210201-19-1s9s592.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=519&fit=crop&dpr=1 754w, https://images.theconversation.com/files/381704/original/file-20210201-19-1s9s592.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=519&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/381704/original/file-20210201-19-1s9s592.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=519&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Pine martens are thought to hunt grey squirrels more readily than reds.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/pine-marten-drinking-lake-forest-1798450855">Beata Farkas/Shutterstock</a></span>
</figcaption>
</figure>
<p><a href="https://reader.elsevier.com/reader/sd/pii/S0304380020304506?token=65D4E8A4AD5ED08A53E7A0359A31A65414B15AB18285A97E020D0CB976E7BF1A903F54EFACC860BFCCAEFAB5F95054B7">A recent study</a> suggested the most efficient way to control grey squirrels is a combination of culling and contraceptives. So no matter how effective an oral contraceptive is, culls are likely to continue. Animal welfare campaigners are <a href="https://petition.parliament.uk/petitions/562294">lobbying the government</a> to at least halt culls during the breeding season, when female grey squirrels have kits in the nest. As it stands, mothers can be killed and their offspring left to starve.</p>
<p>I’ve written <a href="https://theconversation.com/in-defence-of-the-grey-squirrel-britains-most-unpopular-invader-73983">in defence of grey squirrels</a> before, but I support controlling their populations with contraceptives. While I’d prefer nature to provide its own solution, I welcome methods of controlling so-called pest species that minimise pain and stress. Just because a species causes damage doesn’t mean that we can’t manage them with consideration for ethics and welfare.</p><img src="https://counter.theconversation.com/content/154400/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jason Gilchrist does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Squirrel feeders laced with contraceptives could be used to suppress grey squirrels in the UK.Jason Gilchrist, Ecologist, Edinburgh Napier UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1480592020-12-03T16:09:58Z2020-12-03T16:09:58ZAfter wildfires, logging the forest can harm wildlife for up to a decade<figure><img src="https://images.theconversation.com/files/371780/original/file-20201127-23-1o8fcon.jpg?ixlib=rb-1.1.0&rect=46%2C38%2C5129%2C3406&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Burnt trees can be logged and turned into timber and other wood products. But removing them from the forest can have negative impacts on the wildlife.</span> <span class="attribution"><span class="source">THE CANADIAN PRESS/Jason Franson</span></span></figcaption></figure><p>Wildfires have broken many records in the western United States and Canada in the past three years, including the devastating fires that blackened large areas and burned hundreds of buildings in California, Oregon and Washington in September 2020. </p>
<p><a href="https://doi.org/10.1016/j.tree.2005.04.025">Wildfires fundamentally change forests</a>, and they are a natural feature in forested ecosystems around the world. Many species of plants and animals have <a href="https://doi.org/10.1071/AM14027">adapted to the fire regimes of their ecosystems</a>, such as lodgepole pine trees, which germinate more readily after fire, and many woodpeckers that use recently burned forest to forage for bugs and build nests.</p>
<p>However, wildfire is often at odds with human interests, because fires burn trees that might have otherwise been cut down by logging companies. In British Columbia, post-fire salvage logging is often used to recoup the economic losses that come with wildfire, by harvesting the logs for lumber, plywood and pulp. </p>
<p>As researchers who have studied post-fire salvage logging in the Chilcotin Plateau in central B.C., we’ve found that these operations are often much larger and more severe than standard logging practices, and can have <a href="https://doi.org/10.1111/j.1523-1739.2006.00497.x">negative impacts on wildlife</a> — <a href="https://doi.org/10.1016/j.foreco.2020.118272">sometimes lasting for as long as a decade</a>.</p>
<h2>No red squirrels or snowshoe hares</h2>
<p>Our research focused on the prey species that live in these forests — snowshoe hares, red squirrels, mice and voles — and are important food for owls, lynx, marten, fisher and coyotes. Salvage logging led to fewer prey species and lower prey abundances for up to a decade after the fire compared to prey populations in sites that were burned but not salvage logged. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/372370/original/file-20201201-23-16voq0o.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A snowshoe hare" src="https://images.theconversation.com/files/372370/original/file-20201201-23-16voq0o.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/372370/original/file-20201201-23-16voq0o.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/372370/original/file-20201201-23-16voq0o.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/372370/original/file-20201201-23-16voq0o.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/372370/original/file-20201201-23-16voq0o.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/372370/original/file-20201201-23-16voq0o.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/372370/original/file-20201201-23-16voq0o.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Snowshoe hares and other small mammals need standing trees for protection.</span>
<span class="attribution"><span class="source">(Angelina Kelly)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>We found that post-fire salvage logging removed nearly all standing trees from burned areas, making these sites unsuitable for snowshoe hares, red squirrels and southern red-backed voles. These species all need some vertical cover to shelter from predators. Salvage-logged areas supported almost exclusively deer mice, while post-fire regenerating stands had higher species diversity and higher vole populations.</p>
<p>Snowshoe hares and red squirrels recolonized forest sites within nine years of the fire. Snowshoe hare densities were higher in these forests than they were in mature forest sites, but red squirrels were only half as common. Salvage-logged sites, however, had no red squirrels or snowshoe hares nine years after the fire.</p>
<h2>Landscape effects</h2>
<p>The loss of regenerating post-fire habitat to post-fire salvage logging becomes more concerning when considering the scale and timeline of the logging operations. Post-fire salvage logging often occurs quickly following fire as <a href="https://doi.org/10.1111/1365-2664.12945">harvesters attempt to get timber to the market before it decays and loses value</a>. As wildfires are often seen as detrimental by society, harvesters take <a href="https://doi.org/10.1111/j.1523-1739.2006.00497.x">more post-fire timber from larger areas of land than during standard logging</a>. </p>
<figure class="align-center ">
<img alt="Open field with small shrubs and some logs" src="https://images.theconversation.com/files/372371/original/file-20201201-23-1o05j65.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/372371/original/file-20201201-23-1o05j65.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/372371/original/file-20201201-23-1o05j65.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/372371/original/file-20201201-23-1o05j65.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/372371/original/file-20201201-23-1o05j65.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/372371/original/file-20201201-23-1o05j65.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/372371/original/file-20201201-23-1o05j65.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">An area that has been salvage logged after wildfire.</span>
<span class="attribution"><span class="source">(Angelina Kelly)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>In addition, climate change is <a href="https://doi.org/10.1016/j.foreco.2017.03.035">increasing wildfire occurrence and severity globally</a>, including in <a href="https://doi.org/10.1007/s10980-016-0414-6">western North America</a>. As wildfires increase, the potential for large post-fire salvage logging increases. </p>
<p>For example, in 2017, B.C. experienced its largest wildfire season in history, with more than 1.2 million hectares of forest burned. The following year, that record fell, with <a href="https://www2.gov.bc.ca/gov/content/safety/wildfire-status/about-bcws/wildfire-history/wildfire-season-summary">1.3 million hectares burned</a>. With that much land burned, there was a large potential for post-fire salvage logging to impact millions of hectares. </p>
<p>Post-fire salvage logging occurred on the Chilcotin Plateau study area following the large Hanceville Fire of 2017. Large wildfires and the intense post-fire salvage logging that follows those fires have the potential to shift small prey mammal populations across entire landscapes if this trend continues. </p>
<h2>Wildlife shift</h2>
<p>These massive shifts in prey base will almost certainly also affect the forest predators and raptors that require these small mammals as their prey, leading to a large shift in wildlife communities. In related work, we have seen that lynx, marten, fisher and coyotes all shift behaviour and abundance in relation to fires and post-fire salvage. </p>
<figure class="align-center ">
<img alt="Burnt tree trunks with a meadow of wildflowers." src="https://images.theconversation.com/files/372372/original/file-20201201-15-1e5e6fs.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/372372/original/file-20201201-15-1e5e6fs.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/372372/original/file-20201201-15-1e5e6fs.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/372372/original/file-20201201-15-1e5e6fs.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/372372/original/file-20201201-15-1e5e6fs.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/372372/original/file-20201201-15-1e5e6fs.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/372372/original/file-20201201-15-1e5e6fs.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A burned forest that has been left to regenerate.</span>
<span class="attribution"><span class="source">(Angelina Kelly)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Given the importance that post-fire regenerating forests had for snowshoe hares, red squirrels and voles in our study, we stress the importance of policy decisions around post-fire forest management. At present, wildlife considerations are not fully included in post-fire forestry decisions. </p>
<p>Salvage logging was clearly detrimental to the majority of small mammals, and our results suggest that current post-fire practices should be changed.</p><img src="https://counter.theconversation.com/content/148059/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Karen Hodges receives funding from Canada's Natural Sciences and Engineering Research Council and the Habitat Conservation Trust Foundation.</span></em></p><p class="fine-print"><em><span>Angelina Kelly receives funding from The Habitat Conservation Trust Foundation. </span></em></p>Removing trees killed by fires can have long-term consequences for wildlife.Karen Hodges, Professor of Conservation Biology, University of British ColumbiaAngelina Kelly, Master’s Student, Conservation Biology, University of British ColumbiaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1326282020-03-02T11:53:26Z2020-03-02T11:53:26ZHow to help red squirrels fight back against invasive greys – with DNA sequencing<figure><img src="https://images.theconversation.com/files/317803/original/file-20200228-24651-lx87hb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Giedriius / shutterstock</span></span></figcaption></figure><p>The red squirrel is the UK’s only native squirrel species. Unfortunately, they are now a very rare sight across Britain and Ireland, thanks to widespread destruction of their native forests, combined with competition from the larger grey squirrel – an invasive species introduced from North America. It’s also due to the spread of diseases such as the squirrelpox virus, which causes ulcers and scabs and a painful death. </p>
<p>Although grey squirrels carry squirrelpox, they rarely suffer any symptoms. Having been exposed to the disease for a long time, they have developed an “acquired immunity” where their immune systems have learnt to fight it off. This isn’t the case for red squirrels, however, and outbreaks of the virus can kill <a href="https://rb.gy/f2ng6e">more than 80%</a> of a population. This leads to small, fragmented groups that have a higher risk of being wiped out.</p>
<p>But by studying squirrel DNA, particularly if we can work out what makes grey squirrels and some red squirrels immune to the disease, we might be able to find new ways of helping the reds survive.</p>
<p>Since 2016, one of us (Kathryn) has been researching how one isolated group of red squirrels in the town of Formby, Merseyside, has <a href="https://rebrand.ly/8ygluiy">adapted to urban life</a> alongside people. As could be the case for many isolated populations across the UK, this urban population may have genetic inbreeding caused by closely-related individuals mating with each other, which can have knock-on effects on their immune systems. The Formby population has also recently suffered from another <a href="https://rb.gy/0wjj2m">devastating outbreak</a> of squirrelpox.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/317827/original/file-20200228-24701-1g417e4.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/317827/original/file-20200228-24701-1g417e4.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/317827/original/file-20200228-24701-1g417e4.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/317827/original/file-20200228-24701-1g417e4.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/317827/original/file-20200228-24701-1g417e4.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/317827/original/file-20200228-24701-1g417e4.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/317827/original/file-20200228-24701-1g417e4.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/317827/original/file-20200228-24701-1g417e4.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">UK red squirrel population has fallen from 3.5m to just 150,000.</span>
<span class="attribution"><span class="source">Annabel Bligh</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>However, a scientific tool has given us new hope: genome sequencing. A genome is all the DNA in an organism and when it is “sequenced”, this gives us a complete list of everything that makes up the DNA in the chromosomes of either an individual or a whole species. A team of scientists involved in the <a href="https://www.sanger.ac.uk/science/programmes/tree-of-life">Darwin Tree of Life</a> project recently worked with Kathryn to sequence both <a href="https://rb.gy/lrdpww">red</a> and <a href="https://rb.gy/kailzw">grey</a> squirrel genomes, using pieces of spleen collected from squirrels from Formby. </p>
<p>We hope that the genomes will help us to understand the genetic basis for the grey squirrels’ immunity to squirrelpox. More importantly, they may help to explain the <a href="https://rb.gy/0r9st2">resistance</a> found in the small number of red squirrels that have survived previous outbreaks, much like with HIV in humans where a <a href="https://rb.gy/fywrwm">certain combination of genes</a> means that the virus cannot replicate well in some people. The genomes may also assist with captive breeding programmes and reintroductions or translocations in their natural habitats, by helping to establish genetically healthy red squirrel populations.</p>
<h2>How it works</h2>
<p>By comparing the genome sequences against a catalogue of known viral proteins, we can identify whether there are any new “viral insertions”. This is when a virus inserts a copy of its own genome into the DNA of a host cell and becomes inherited, which will therefore change the genome of the host, and this is what we are looking to find.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"972114794206711809"}"></div></p>
<p>We can then analyse samples collected from individual squirrels, to see whether these viruses are present or not in their genomes. This can also be explored and compared across red squirrel populations and even between different squirrel species. Depending on where the viruses are found in the genome and whether they are active – in other words, causing the host cell to make new viruses – this may impact the red squirrels’ immunity and so their susceptibility to diseases.</p>
<p>These, or similar, methods have already been used successfully in other species, for example in <a href="https://rebrand.ly/ts6b7wa">horses</a>, <a href="https://rebrand.ly/xqe9xwo">canines</a> and <a href="https://rb.gy/nnfefj">koalas</a>. They also have the potential to be used in future projects for other endangered species, as new genomes are sequenced.</p>
<p>The newly published genome sequences open up numerous exciting research opportunities, including studying population diversity, responses to diseases, and evolutionary changes due to environmental stresses. The findings can hopefully help conservationists to protect the endangered red squirrel and ensure their long-term survival in the UK.</p><img src="https://counter.theconversation.com/content/132628/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kathryn Fingland worked with the Wellcome Sanger Institute on the red and grey squirrel genome sequencing project.</span></em></p><p class="fine-print"><em><span>Rachael Tarlinton has received funding for squirrel retrovirus projects from the zebra foundation, for dog retroviruses from the royal society of veterinary surgeons trust and for koalas from the Queensland department of the environment and heritage </span></em></p><p class="fine-print"><em><span>Adam Blanchard does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Scientists hope to learn what makes certain red squirrels able to survive squirrelpox. Kathryn Fingland, Doctoral Researcher in Wildlife Conservation & Ecology, Nottingham Trent UniversityAdam Blanchard, Assistant Professor of Computational Biology, University of NottinghamRachael Tarlinton, Associate Professor in Veterinary Virology, University of NottinghamLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1310642020-02-26T13:49:25Z2020-02-26T13:49:25ZGrey squirrels are oblivious to threat from pine martens – giving native reds the advantage<figure><img src="https://images.theconversation.com/files/315471/original/file-20200214-10980-bhybfr.jpg?ixlib=rb-1.1.0&rect=0%2C408%2C1400%2C1270&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A European pine marten climbing a tree in the Levoča Mountains, Slovakia.</span> <span class="attribution"><span class="source">František Koneval</span>, <span class="license">Author provided</span></span></figcaption></figure><p>For as long as modern humans have been moving around the planet, we’ve been bringing animals, plants and microorganisms with us. But by introducing invasive species to ecosystems in which they did not evolve, we’ve unwittingly created problems that we now spend a great deal of effort and resources trying to rectify. </p>
<p>The North American grey squirrel is one such invasive species that was brought to Britain and Ireland during the 19th and 20th centuries. Since their introduction, grey squirrels have replaced the native red squirrel across much of its former range, mainly by <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/ece3.1216">transmitting squirrel pox to reds</a>, a deadly virus to which greys are immune. Almost all attempts to counter historic blunders with grey squirrels have been met with limited success, but it would seem that nature already has a solution.</p>
<p>Until recently, the European pine marten was a little-known member of the weasel family that lives in trees and is restricted within the British Isles to the northern reaches of Scotland and the western coast of Ireland. But in recent years, it has started to reclaim some of its former range. In parts of Ireland and Scotland where this native predator has recovered, there have been subsequent <a href="https://royalsocietypublishing.org/doi/full/10.1098/rspb.2017.2603">declines in grey squirrel populations</a>, allowing reds to recover. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/314445/original/file-20200210-109891-tl9js9.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/314445/original/file-20200210-109891-tl9js9.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/314445/original/file-20200210-109891-tl9js9.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/314445/original/file-20200210-109891-tl9js9.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/314445/original/file-20200210-109891-tl9js9.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/314445/original/file-20200210-109891-tl9js9.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/314445/original/file-20200210-109891-tl9js9.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Pine martens are natural predators in Britain and Ireland. These forest specialists are returning to their old haunts after centuries of decline.</span>
<span class="attribution"><span class="source">Joshua P Twining</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>For conservationists, it almost sounds too good to be true. But why do pine martens seem to benefit native red squirrels at the expense of invasive greys?</p>
<h2>Striking fear into red squirrels</h2>
<p>Researchers sifting through masses of pine marten faeces demonstrated that pine martens eat both squirrel species, but <a href="https://www.researchgate.net/publication/257997086_A_non-invasive_approach_to_determining_pine_marten_abundance_and_predation">they tend to eat more grey than red squirrels</a>. We know <a href="https://link.springer.com/article/10.1007/s10344-019-1289-z">pine martens are opportunistic omnivores</a>, switching food throughout the year and consuming whatever is available. So it’s probably not the preferences of pine martens that lead them to eat more grey squirrels, but the availability of the squirrels themselves. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-the-pine-marten-is-not-every-red-squirrels-best-friend-110209">Why the pine marten is not every red squirrel's best friend</a>
</strong>
</em>
</p>
<hr>
<p>One way that prey species avoid predators is with chemical signals. Predators use scent cues to mark territories and communicate with one another, but prey animals have evolved behavioural responses to these scent cues. By eavesdropping on these chemical signals, prey species can alter their behaviour and avoid predators, increasing their chances of survival. Could the grey squirrel, an animal not native to Britain or Ireland, be naive to the risk posed by the pine marten?</p>
<p>Armed with camera traps, squirrel feeders and a solution of pine marten poo, we set out to find out if this was the case. We repeated the experiment at 20 different locations across Northern Ireland, amassing more than 8,000 minutes of squirrel footage. The results are <a href="https://royalsocietypublishing.org/doi/10.1098/rsos.191841">published in Royal Society Open Science</a>.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/315328/original/file-20200213-10976-1fmn7dm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/315328/original/file-20200213-10976-1fmn7dm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/315328/original/file-20200213-10976-1fmn7dm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/315328/original/file-20200213-10976-1fmn7dm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/315328/original/file-20200213-10976-1fmn7dm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/315328/original/file-20200213-10976-1fmn7dm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/315328/original/file-20200213-10976-1fmn7dm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Grey squirrels didn’t register a threat when in sniffing distance of pine marten scent.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/eastern-gray-squirrel-stealing-nuts-northumberland-278173925">Will Howe/Shutterstock</a></span>
</figcaption>
</figure>
<p>Emerging red-eyed from our lab, we realised that red squirrels showed a clear fear response to pine marten scent while greys didn’t. Reds visited feeders less, fed for shorter periods of time and were more vigilant – standing on their hind legs with their head upright and tail twitching from side to side. Meanwhile, the greys continued as if nothing had changed. In some cases, grey squirrel visits to feeding stations actually increased while their vigilance decreased around pine marten scent.</p>
<p>Failing to recognise the scent of a predator as a threat leaves the grey squirrels vulnerable. In hindsight though, their behaviour isn’t surprising. Red squirrels and pine martens have shared the same evolutionary landscape for millennia – we would expect them to be aware of each other. But grey squirrels and pine martens have co-existed in the same place for a mere blink of the eye. Although the pine marten predates red and grey squirrels, they have more success in catching greys because they appear oblivious to the threat.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/314446/original/file-20200210-109896-nsus6a.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/314446/original/file-20200210-109896-nsus6a.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/314446/original/file-20200210-109896-nsus6a.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/314446/original/file-20200210-109896-nsus6a.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/314446/original/file-20200210-109896-nsus6a.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/314446/original/file-20200210-109896-nsus6a.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/314446/original/file-20200210-109896-nsus6a.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A red squirrel flags its tail and releases alarm calls after spotting a pine marten in County Fermanagh, Northern Ireland.</span>
<span class="attribution"><span class="source">Joshua P Twining</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Healthy native predator populations have wide ranging benefits to the environment they inhabit. Conservation efforts are helping <a href="https://science.sciencemag.org/content/346/6216/1517">predators to recover in parts of Europe</a>, ensuring they can restore and regulate ecosystems. If the recovery of a small weasel can have such benefits, there is immense potential for <a href="https://www.researchgate.net/publication/259652500_Status_and_Ecological_Effects_of_the_World's_Largest_Carnivores">larger predators like lynx and wolves to restore balance</a> to fragmented and degraded ecosystems.</p>
<p>Pine martens aren’t a panacea for red squirrels though. Human-led efforts will still be important in red squirrel conservation, especially because prey species can develop responses to new predators <a href="https://www.researchgate.net/publication/230620045_Behavioral_responses_of_native_prey_to_disparate_predators_Naivet_and_predator_recognition">in just a few generations</a>. Who knows whether grey squirrels will develop anti-predator behaviours.</p>
<p>But if, like the red squirrel, greys learn to recognise and avoid the pine marten, they could one day learn to survive alongside it. Useful though they may be, the pine marten – or any native predator – is more than a solution to a human-made problem. They are an essential and iconic part of the natural world. The conservation and recovery of predators may not always be easy, but in a human-dominated world, we must learn to live alongside what precious biodiversity we have left.</p><img src="https://counter.theconversation.com/content/131064/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Joshua P Twining received funding from the Department of Education, Northern Ireland.
David Tosh is the Research Coordinator at National Museums Northern Ireland, he conceptualised and supervised this work. Funding for the data collection of this project was crowdfunded through a Kickstarter campaign:
<a href="https://www.kickstarter.com/projects/318099790/the-squirrel-predator-prey-project">https://www.kickstarter.com/projects/318099790/the-squirrel-predator-prey-project</a></span></em></p>Where pine martens have recovered, red squirrels have tended to benefit while grey squirrels have declined. Scientists weren’t sure why – until now.Joshua P Twining, PhD researcher in Ecology, Queen's University BelfastLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1150532019-04-08T14:07:33Z2019-04-08T14:07:33ZCamera traps are revealing the secret lives of Britain’s mammals<figure><img src="https://images.theconversation.com/files/268089/original/file-20190408-2905-32uhil.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C3888%2C2590&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/red-fox-british-countryside-28943083?src=BvDK1yqZHn762Wf2JYqHIA-1-25">Graham Taylor/Shutterstock</a></span></figcaption></figure><p><a href="https://www.wwf.org.uk/sites/default/files/2018-10/wwfintl_livingplanet_full.pdf">Wildlife populations are declining</a> globally, but it’s not all doom and gloom. We’re in the midst of an exciting time for UK mammals. <a href="https://www.bbc.co.uk/news/uk-england-essex-47602112">There are beavers</a> and <a href="https://www.leicestermercury.co.uk/news/local-news/wild-boar-spotted-roaming-free-2637408">wild boar living free</a> in the UK again. <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/mam.12150">Otter populations</a> are recovering and can now be found in all English counties. <a href="https://www.bbc.co.uk/news/science-environment-35386042">Polecats are expanding their range</a> and pine martens, with a little assistance, <a href="https://theconversation.com/why-the-pine-marten-is-not-every-red-squirrels-best-friend-110209">are growing in number</a>. Nevertheless, the information we have on many of these species is still very limited, making it difficult to understand the bigger picture.</p>
<p>With a growing human population, it’s more important than ever that scientists and the public work together to monitor mammals effectively. Only with accurate information can conservation benefit both wildlife and the people living alongside it.</p>
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Read more:
<a href="https://theconversation.com/how-to-stop-the-humble-hedgehog-disappearing-from-british-gardens-and-countryside-forever-89432">How to stop the humble hedgehog disappearing from British gardens and countryside forever</a>
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<p>Unfortunately, there’s little data on many British mammal species, and this prevents precise <a href="https://www.mammal.org.uk/wp-content/uploads/2018/06/MAMMALS-Technical-Summary-FINALNE-Verision-FM2.pdf">population estimates</a>. With limited historical data, too, it’s difficult to know if populations are becoming more or less abundant and why. Without this information, it’s hard to say if conservation is needed. Important debates on issues such as <a href="https://theconversation.com/badger-cull-alone-wont-work-for-eradicating-bovine-tb-but-this-might-107472">badger culling</a> and <a href="https://theconversation.com/no-wonder-fox-hunting-is-still-prevalent-the-ban-is-designed-to-fail-british-wildlife-110454">fox hunting</a> may also be ill informed.</p>
<p>Many mammals are nocturnal and elusive so people are unlikely to come across them. More visible species, such as rabbits or grey squirrels, are so common that people are unlikely to keep a record of sightings. To ensure the successful protection and management of Britain’s mammal community, there need to be effective ways of monitoring them long term.</p>
<h2>Citizen camera traps</h2>
<p>One technique that has proved <a href="https://royalsocietypublishing.org/doi/full/10.1098/rsos.181748">successful</a> in the study of mammals is the use of camera traps. These are <a href="https://zslpublications.onlinelibrary.wiley.com/doi/full/10.1002/rse2.20">motion-sensitive</a> cameras that are triggered to take a photograph or short film when an animal moves in front of them. These cameras are battery powered and can be left in place for weeks or even months at a time, recording wildlife.</p>
<p>Although some animals seem curious about the cameras, they cause less disturbance than humans would. Once set up, a camera trap can collect lots of footage – meaning <a href="https://zslpublications.onlinelibrary.wiley.com/doi/full/10.1002/rse2.106">large amounts of data</a> for scientists to search through to identify species. This is one area in which the public can help.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1100489709640445953"}"></div></p>
<p>I recently started working on <a href="http://www.MammalWeb.org">MammalWeb</a> – a citizen science project that invites people to help build a better understanding of the UK’s mammals through camera trapping. People can participate by setting up a camera trap in their garden, or on any land they have permission to access. This makes it possible to have more cameras in the field, spread out across a wider area than any single researcher could manage on their own, generating a more comprehensive data set. Everyone, including those without their own camera trap, can contribute by identifying which animals are present in photos collected by other participants.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/267954/original/file-20190407-115800-w9t9hf.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/267954/original/file-20190407-115800-w9t9hf.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/267954/original/file-20190407-115800-w9t9hf.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/267954/original/file-20190407-115800-w9t9hf.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/267954/original/file-20190407-115800-w9t9hf.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/267954/original/file-20190407-115800-w9t9hf.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/267954/original/file-20190407-115800-w9t9hf.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A red fox (<em>Vulpes vulpes</em>) with its prey: a common pheasant (<em>Phasianus colchicus</em>).</span>
<span class="attribution"><span class="source">Roland Ascroft</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>There are over 500,000 photos in the MammalWeb database – nearly 250,000 uploaded by members of the public, and others by researchers seeking help with classifying species in images they’ve collected. More than 500 people have helped make 500,000 classifications, but as images must be classified by multiple people to <a href="https://zslpublications.onlinelibrary.wiley.com/doi/full/10.1002/rse2.84">ensure accuracy</a>, more classifications are always needed.</p>
<p>Participants have recorded 34 mammal species, ranging from the largest UK land mammal – the red deer – right down to some of the smallest, such as bank voles, captured using specially modified camera traps.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/267953/original/file-20190407-115781-vdjrb9.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/267953/original/file-20190407-115781-vdjrb9.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/267953/original/file-20190407-115781-vdjrb9.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/267953/original/file-20190407-115781-vdjrb9.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/267953/original/file-20190407-115781-vdjrb9.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/267953/original/file-20190407-115781-vdjrb9.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/267953/original/file-20190407-115781-vdjrb9.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A small bank vole (<em>Myodes glareolus</em>) captured by a modified camera trap.</span>
<span class="attribution"><span class="source">Roland Ascroft</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Many of the participants were surprised by what the animals were doing in their own back gardens. There’s the typical predatory behaviour of foxes hunting pheasants and the more unusual behaviour of badgers predating hedgehogs. This behaviour among badgers may be contributing to <a href="https://www.nature.com/articles/s41598-018-30130-4">a decline in hedgehog populations</a>, but the camera traps have found evidence that they can coexist happily, too.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/267956/original/file-20190407-115773-11bsfj5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/267956/original/file-20190407-115773-11bsfj5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/267956/original/file-20190407-115773-11bsfj5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/267956/original/file-20190407-115773-11bsfj5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/267956/original/file-20190407-115773-11bsfj5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/267956/original/file-20190407-115773-11bsfj5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/267956/original/file-20190407-115773-11bsfj5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A badger (<em>Meles meles</em>) and hedgehog (<em>Erinaceus europaeus</em>) sharing food.</span>
<span class="attribution"><span class="source">Terry Wright</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>One particularly surprising find was a North American raccoon (<em>Procyon lotor</em>), captured living wild in the north-east of England. Thanks to these records, the authorities were able to locate the raccoon and transfer it to a local zoo to be looked after.</p>
<p>This highlights how easily wild mammals can go unobserved. It’s unknown how long the raccoon was roaming free and, without the aid of the public and their camera traps, we may never have known about it. While a single raccoon may not seem like a serious conservation issue, non-native species can spread rapidly, with serious consequences for native wildlife.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/267952/original/file-20190407-115800-gdz28l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/267952/original/file-20190407-115800-gdz28l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/267952/original/file-20190407-115800-gdz28l.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/267952/original/file-20190407-115800-gdz28l.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/267952/original/file-20190407-115800-gdz28l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/267952/original/file-20190407-115800-gdz28l.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/267952/original/file-20190407-115800-gdz28l.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Spotted: one very lost raccoon.</span>
<span class="attribution"><span class="source">MammalWeb contributors</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>The raccoon is not the only American visitor to have made itself at home in the UK. American mink, which are <a href="https://www.bbc.co.uk/news/uk-wales-39968853">threatening water vole populations</a>, have been recorded, and American grey squirrels, which compete with native red squirrels, are the most common mammal sighted on MammalWeb – although recovering pine marten populations may help to balance the odds and <a href="https://royalsocietypublishing.org/doi/pdf/10.1098/rspb.2017.2603">aid red squirrel</a> recovery.</p>
<p>Volunteers are assisting <a href="https://www.naturespy.org/">NatureSpy</a>, a non-profit organisation working on wildlife research and community engagement that MammalWeb is partnering with, in its search for the elusive pine marten in North Yorkshire as part of their Yorkshire Pine Marten Support Programme which followed <a href="https://www.theguardian.com/world/2017/aug/07/rare-pine-marten-caught-on-camera-in-yorkshire-for-first-time-in-35-years">video footage of a single pine marten in 2017</a>. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/268088/original/file-20190408-2914-1rkfj9w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/268088/original/file-20190408-2914-1rkfj9w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/268088/original/file-20190408-2914-1rkfj9w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/268088/original/file-20190408-2914-1rkfj9w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/268088/original/file-20190408-2914-1rkfj9w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/268088/original/file-20190408-2914-1rkfj9w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/268088/original/file-20190408-2914-1rkfj9w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Yet to appear in new camera trap footage, the elusive pine marten (<em>Martes martes</em>).</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/pine-marten-martes-highland-scotland-107261963?src=YVOSSJ2n6WcdbqUKBu9UbA-1-7">Mark Caunt/Shutterstock</a></span>
</figcaption>
</figure>
<p>There hasn’t been another caught on camera yet, but continually monitoring the area offers the best chance of spotting the animals as they move into new areas. This will help conservationists understand where and when this species is dispersing and where help can be given.</p>
<p>Camera traps offer fascinating insights into the secret lives of Britain’s mammals. With the help of ordinary people, we can all learn more about them, and how to look after them well into the future.</p><img src="https://counter.theconversation.com/content/115053/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sian Green has received funding from the Natural Environmental Research Council (NERC) through the IAPETUS doctoral training partnership and works with MammalWeb.</span></em></p>Camera traps allow citizen scientists to peek into the hidden lives of Britain’s mammals.Sian Green, PhD Researcher in Wildlife Conservation, Durham UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1102092019-02-12T14:54:42Z2019-02-12T14:54:42ZWhy the pine marten is not every red squirrel’s best friend<figure><img src="https://images.theconversation.com/files/255061/original/file-20190122-100270-1a4iskq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The pine marten – cute but cunning.</span> <span class="attribution"><a class="source" href="https://flic.kr/p/qFm9JV">Karen Bullock/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span></figcaption></figure><p>Pine martens are <a href="https://www.theguardian.com/environment/2018/aug/15/pine-marten-spotted-in-northumberland-for-first-time-in-90-years">returning</a> <a href="https://www.vwt.org.uk/species/pine-marten/">to areas of the UK</a> after an absence of nearly a century. Following releases in <a href="https://www.bbc.co.uk/news/uk-wales-40188235">mid-Wales</a> during 2015, reintroductions are proposed in <a href="https://www.cnp.org.uk/blog/win-or-bust-returning-red-squirrel-snowdonia">north Wales</a> and <a href="https://www.theguardian.com/environment/2018/nov/25/pine-martens-forest-of-dean-return-of-a-predator">southern England</a> for 2019.</p>
<p>The pine marten is a small native carnivore that inhabits a range of woodland habitats. It’s an excellent climber and often nests within tree cavities. This opportunistic predator has a <a href="https://www.researchgate.net/publication/327967568_The_diet_of_denning_female_European_pine_martens_Martes_martes_in_Galloway_Forest_District_South_West_Scotland_Great_Britain">varied diet</a> including fruit, eggs, songbirds and small mammals.</p>
<p>By the 1920s, pine martens were virtually extinct in the UK after centuries of persecution to protect game birds and poultry. Only a population in north-west Scotland and small numbers in northern Wales and England survived. With UK legal protection, <a href="https://www.nature.scot/plants-animals-and-fungi/mammals/land-mammals/pine-marten">their range has expanded</a> since the 1980s, increasing their encounters with the grey squirrel.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/258456/original/file-20190212-174851-12l9wb1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/258456/original/file-20190212-174851-12l9wb1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/258456/original/file-20190212-174851-12l9wb1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/258456/original/file-20190212-174851-12l9wb1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/258456/original/file-20190212-174851-12l9wb1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/258456/original/file-20190212-174851-12l9wb1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/258456/original/file-20190212-174851-12l9wb1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The introduced grey squirrel has caused native red squirrel decline in the British Isles.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/cute-grey-squirrel-eating-park-455377972?src=duDGN56W9W-Sj8jK8_jJpg-1-0">Vinnikava Viktoryia/Shutterstock</a></span>
</figcaption>
</figure>
<p>Since George Monbiot penned “<a href="https://www.theguardian.com/environment/2015/jan/30/how-to-eradicate-grey-squirrels-without-firing-a-shot-pine-martens">how to eradicate grey squirrels without firing a shot</a>” in 2015, the media has courted the charismatic mammal as the <a href="https://www.theguardian.com/environment/2018/mar/07/return-of-pine-martens-could-save-britains-red-squirrels-say-scientists">saviour</a> for the UK’s embattled red squirrels.</p>
<p>The media message is simple: the return of pine martens will <a href="https://www.theguardian.com/environment/2018/mar/07/return-of-pine-martens-could-save-britains-red-squirrels-say-scientists">herald the</a> <a href="https://www.thetimes.co.uk/article/pine-martens-invited-back-to-feast-on-grey-squirrels-d26tw03vr">decline</a> or even <a href="https://www.telegraph.co.uk/science/2018/03/07/predatory-pine-martens-could-save-red-squirrel/">eradication</a> of grey squirrels, which, since their arrival from North America in 1876, have caused regional <a href="https://theconversation.com/grey-squirrels-are-bad-for-the-british-countryside-full-stop-75470">extinctions of the native red squirrel</a>. That’s because pine martens supposedly prefer eating greys, while leaving reds alone.</p>
<p>The optimism around pine martens in the UK originated from research in <a href="https://link.springer.com/article/10.1007/s10531-014-0632-7">Ireland</a> and <a href="https://www.researchgate.net/publication/323615222_The_enemy_of_my_enemy_is_my_friend_Native_pine_marten_recovery_reverses_the_decline_of_the_red_squirrel_by_suppressing_grey_squirrel_populations">Scotland</a>. In Scotland, scientists studied forests containing pine martens, red squirrels and grey squirrels. The more pine martens they recorded using a woodland area, the more likely they were to find red squirrels and the less likely grey squirrels were to be there. Like earlier <a href="https://theconversation.com/resurgent-pine-martens-could-be-good-news-for-red-squirrels-46051">Irish studies</a>, this suggested that pine martens suppress grey squirrel populations to the overall benefit of red squirrels. </p>
<p>However, that’s not quite the whole story. There’s a desire in the media to find <a href="https://www.sciencedirect.com/science/article/abs/pii/S0006320712001462">heroes and villains in nature</a> which simplifies the situation and obscures the potential impact of a returning predator on British wildlife and livestock. Sadly, ecology and conservation are rarely simple and the restoration of pine martens will not always follow a script.</p>
<h2>Red squirrels on the menu?</h2>
<p>The <a href="https://www.researchgate.net/publication/323615222_The_enemy_of_my_enemy_is_my_friend_Native_pine_marten_recovery_reverses_the_decline_of_the_red_squirrel_by_suppressing_grey_squirrel_populations%20are%20careful">Scottish pine marten researchers</a> make clear that pine martens sometimes eat red squirrels. In a small number of other <a href="https://www.researchgate.net/publication/280294387_A_long-term_study_of_the_winter_food_niche_of_the_pine_marten_Martes_martes_in_northern_boreal_Finland">studies</a> conducted <a href="http://rcin.org.pl/dlibra/docmetadata?id=11728">elsewhere in Europe</a>, reds were in fact a significant seasonal component of pine marten diet – up to 53% in one case.</p>
<p>It’s therefore incorrect to suggest, <a href="https://pine-marten-recovery-project.org.uk/our-work/faqs">as some conservation groups have</a>, that dietary studies show pine martens very rarely eat red squirrels. The reality is that predation rates reflect the relative abundance of red squirrels to other prey, encounter rates and local habitat characteristics.</p>
<p>Why grey squirrels have declined in the presence of pine martens <a href="https://theconversation.com/resurgent-pine-martens-could-be-good-news-for-red-squirrels-46051">remains uncertain</a>. The impact of martens on greys may vary geographically and it’s unwise to simply extrapolate the findings from <a href="https://www.researchgate.net/publication/323615222_The_enemy_of_my_enemy_is_my_friend_Native_pine_marten_recovery_reverses_the_decline_of_the_red_squirrel_by_suppressing_grey_squirrel_populations">Scotland</a> and <a href="https://link.springer.com/article/10.1007/s10531-014-0632-7">Ireland</a> to the rest of the British Isles without a note of caution. Suggesting the pine marten is <a href="https://www.theguardian.com/environment/2018/mar/07/return-of-pine-martens-could-save-britains-red-squirrels-say-scientists">the best long-term solution</a> for grey squirrel control in England is premature and requires more research to confirm.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/255057/original/file-20190122-100288-15n3phc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/255057/original/file-20190122-100288-15n3phc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/255057/original/file-20190122-100288-15n3phc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=597&fit=crop&dpr=1 600w, https://images.theconversation.com/files/255057/original/file-20190122-100288-15n3phc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=597&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/255057/original/file-20190122-100288-15n3phc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=597&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/255057/original/file-20190122-100288-15n3phc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=750&fit=crop&dpr=1 754w, https://images.theconversation.com/files/255057/original/file-20190122-100288-15n3phc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=750&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/255057/original/file-20190122-100288-15n3phc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=750&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">An owl sanctuary in Northern Ireland had an unwelcome visit from a pine marten.</span>
<span class="attribution"><a class="source" href="https://www.facebook.com/worldofowls1/">World of Owls</a>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Pine martens have been absent from much of England for <a href="https://www.mammal.org.uk/species-hub/full-species-hub/discover-mammals/species-pine-marten/">around 100 years</a>, a period of significant agricultural and urban change. Landscapes have altered dramatically and many potential prey species have <a href="https://www.rspb.org.uk/birds-and-wildlife/wildlife-guides/bird-a-z/lapwing/population-trends/">regionally declined</a>. Pine marten predation upon these could therefore prove to be locally significant.</p>
<p>This should not be a barrier to reintroducing pine martens. Instead, it reinforces the need for informed discussions with all interest groups likely to be affected. We must acknowledge that as a last resort, <a href="https://community.rspb.org.uk/ourwork/b/martinharper/posts/tough-choices-a-follow-up-comment-about-values-and-motivations">lethal control of predators</a> may be necessary to conserve rare species such as some ground nesting birds.</p>
<p>As the pine marten becomes more common in the UK and Ireland, inevitably there will be scenarios where <a href="https://www.nature.scot/plants-animals-and-fungi/mammals/land-mammals/pine-marten">lethal intervention is unavoidable</a>. A pine marten predating a seabird colony was shot in 2018 under licence to protect an internationally important breeding population.</p>
<p>Measures to prevent predation of poultry or game birds are frequently recommended where pine marten restoration is occurring. These include the installation of electric fencing, cutting back branches overhanging pens and ensuring that wire netting has no holes martens could get through.</p>
<p>While these management recommendations are useful, many people may find it difficult to implement them. As a result, any negative impacts of a returning arboreal predator will <a href="https://www.longfordleader.ie/video/home/234811/video-longford-man-devastated-following-pine-martens-attack-on-his-hens-and-partridges.html">fall heavily</a> upon a handful of poultry owners.</p>
<p>The return of the pine marten <a href="https://www.bbc.co.uk/news/uk-scotland-highlands-islands-44532518">may also complicate</a> the conservation or reintroduction of other species. Although the location and other details are confidential, there were concerns that a pine marten was adversely affecting a red squirrel conservation programme after an individual was found to be regularly visiting release enclosures.</p>
<p>As pine martens naturally spread from Scotland into northern England, <a href="https://www.europeansquirrelinitiative.org/wp-content/uploads/2018/06/ESI-Pine-Marten-A-Revised-Position-.pdf">adaptive and measured responses</a> will be needed to responsibly manage their return. An approach to conservation that’s media-friendly but built on limited evidence rarely works, and certainly won’t in pine marten restoration.</p><img src="https://counter.theconversation.com/content/110209/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>We should welcome a native predators’ return across the British Isles, while at the same time being honest about the implications.Craig Shuttleworth, Honorary Visiting Research Fellow, Bangor UniversityMatt Hayward, Associate professor, University of NewcastleLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1075352018-11-30T10:01:55Z2018-11-30T10:01:55ZRare woodland wildlife at risk because of 50-year-old tree felling rules<figure><img src="https://images.theconversation.com/files/247977/original/file-20181129-170232-b5gv53.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/curious-red-squirrel-peeking-behind-tree-363182720?src=tDW2Y1lP9zJ7wLi1Hdg-xA-1-102">VOJTa Herout/Shutterstock</a></span></figcaption></figure><p>In the UK <a href="https://www.rsne.org.uk/squirrels-and-law">it is illegal</a> to deliberately kill or injure <a href="https://www.redsquirrelsunited.org.uk/">red squirrels</a>, disturb them while they are using a nest, or destroy their nests. Yet, although the <a href="https://www.legislation.gov.uk/ukpga/1981/69">1981 Wildlife and Countryside Act</a> provides these protections, there is a legal anomaly in England and Wales – one that can potentially undermine the conservation of the red squirrel, along with every other rare and endangered forest plant or animal species. Although rare woodland species are protected, the habitat they dwell in is generally not.</p>
<p>Timber harvesting requires a licence – although there are some very <a href="https://naturalresources.wales/media/682351/tree-felling-getting-permission-booklet.pdf">limited exceptions</a> where this permission is not needed, for example <a href="https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/699889/treefellingaugust.pdf">due to</a> public safety, or where small volumes of wood are being cut. But under the 1967 Forestry Act, applications in England and Wales <a href="https://www.legislation.gov.uk/ukpga/1967/10/part/II/crossheading/restriction-of-felling">cannot be refused</a> for “the purpose of conserving or enhancing” flora or fauna (though they can be refused for this purpose in Scotland). Nor can licence conditions be imposed for this reason. No matter how rare, how vulnerable or how much effort has gone into the regional conservation of a species, there are no exceptions to this.</p>
<p>A timber felling licence does not sweep aside the <a href="http://jncc.defra.gov.uk/PDF/rs_law_ewn.pdf">legal protection</a> that animals such as the red squirrel have – and a precautionary approach is advisable when felling in woodlands containing this species. Nevertheless, the possession of a felling licence opens a loophole because the wildlife legislation protecting the red squirrel provides the <a href="https://www.cps.gov.uk/legal-guidance/wildlife-offences">defence of</a> “incidental result of an otherwise lawful operation”. So, with a licence in hand, <a href="https://www.dailypost.co.uk/news/north-wales-news/fears-baby-red-squirrels-could-14936025">woodlands containing this threatened species</a> <a href="http://northernredsquirrels.org.uk/northnews4.pdf">can be clearfelled</a> because tree harvesting is a lawful operation. </p>
<h2>Changing the rules</h2>
<p>The solution is clearly to amend the Forestry Act to better align timber harvesting and wildlife protection laws. Harmonising UK forestry legislation would allow for better timing, methods and patterns of tree harvesting to be guaranteed in habitats containing any rare species. Additionally, while licensing authorities currently can only assess each felling licence application in isolation, legislative change would enable the cumulative impact of granting a licence to be considered in relation to felling that had previously been approved. This stops management of rare woodland species on specific sites being at the mercy of timber prices and market economics.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/247979/original/file-20181129-170238-q5lu9a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/247979/original/file-20181129-170238-q5lu9a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/247979/original/file-20181129-170238-q5lu9a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/247979/original/file-20181129-170238-q5lu9a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/247979/original/file-20181129-170238-q5lu9a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/247979/original/file-20181129-170238-q5lu9a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/247979/original/file-20181129-170238-q5lu9a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/247979/original/file-20181129-170238-q5lu9a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Pine trees are felled near Glencoe, in the Highlands of Scotland.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/pine-tree-forestry-exploitation-sunny-day-341954180?src=o4zEYrwSwO-pS9G2dstENg-1-2">lowsun/Shutterstock</a></span>
</figcaption>
</figure>
<p>Commercially managed forests provide jobs and <a href="https://www.forestresearch.gov.uk/tools-and-resources/statistics/statistics-by-topic/timber-statistics/uk-wood-production-and-trade-provisional-figures/">produce valuable products</a>. As the <a href="https://www2.gov.scot/Topics/farmingrural/Forestry/completingdevolution/forestrylandmanagementbill">modernised laws</a> in Scotland show, the forest industry operates quite successfully where timber harvesting licence applications <a href="https://www.forestry.gov.uk/pdf/treefellingaugust.pdf/$FILE/treefellingaugust.pdf">can consider wildlife impacts</a>. Amendment in England and Wales would deliver similar integration. </p>
<p>Consequently, the ethical credentials of the timber harvesting industry would be strengthened. In an age where <a href="https://e360.yale.edu/features/greenwashed-timber-how-sustainable-forest-certification-has-failed">consumers want confidence</a> that timber products they purchase have not destroyed wildlife populations, this is essential. It is already commonplace for products made of UK-sourced wood to have the <a href="https://www.fsc-uk.org/en-uk/about-fsc/what-is-fsc">Forest Stewardship Council (FSC) logo</a>. The FSC signifies the wood is from sustainable sources managed with a high regard for wildlife conservation. So amendment of the 1967 Forestry Act would give greater consumer confidence in supply chains and also reinforce the credibility of the global FSC forest certification scheme itself. </p>
<h2>Balancing priorities</h2>
<p>Since the 1980s, the forestry sector has increasingly balanced commercial, societal and environmental imperatives. Consequently there will be times, should the law change, when refusal of a logging license to conserve biodiversity is an unavoidable trade off. Here it is important to stress that the forest industry <a href="https://www.forestry.gov.uk/england-grants">receives state grants</a> to support crop establishment and protection. The taxpayer therefore has a right to ensure that forests are managed sympathetically for wildlife. We should not forget that commercial plantations can be <a href="https://www.woodlandtrust.org.uk/visiting-woods/trees-woods-and-wildlife/woodland-habitats/plantations/">vitally important for wildlife</a> and without them many species would be much rarer.</p>
<p>On the other hand, some felling will inevitably still be licensed even though operations will adversely affect individual animals of a protected species through habitat loss or alteration. Although such decisions may be unpopular with local people, it is common for <a href="https://www.nature.com/scitable/knowledge/library/ethics-of-wildlife-management-and-conservation-what-80060473">wildlife management strategies</a> to focus on population level conservation targets rather than at the individual animal level.</p>
<p>I believe an amendment to the Forestry Act is overdue. Regulatory change will empower authorities with the legal tools to achieve a better balance between often competing forest management objectives. It will <a href="https://www.wildlifetrusts.org/nature-recovery-network">benefit wildlife</a> and the UK timber industry too.</p><img src="https://counter.theconversation.com/content/107535/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Craig Shuttleworth currently works in the Red Squirrels United project EU LIFE14 NAT/UK/000467.
He is an advisor to European Squirrel Initiative, Red Squirrels Survival Trust and the Zoological Society of Wales.
He is urging Government to amend the 1967 Forestry Act.</span></em></p>The 1967 Forestry Act is a barrier to integrated forest management in England & Wales.Craig Shuttleworth, Honorary Visiting Research Fellow, Bangor UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/960842018-05-03T22:29:00Z2018-05-03T22:29:00ZHow the hard work of wild animals benefits us too<figure><img src="https://images.theconversation.com/files/217599/original/file-20180503-153895-mwmz4a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The male cardinal tenderly feeding his mate is just one example of the hard work wild animals undertake in springtime. That work often benefits humans.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>Like other nature lovers and rural residents, I have been marvelling at the many animal courtships and other mating preparations that accompany the arrival of spring in the Northern Hemisphere.</p>
<p>The brilliant-red male cardinals who seek out the best seeds and then tenderly feed their female mates, beak-to-beak. The robins who dutifully solicit and assess building supplies as they carefully construct their nests. The squirrels who remember which nuts have been buried where — <a href="https://www.sciencedaily.com/releases/2017/09/170913192952.htm">and whose organizational skills rival the best administrative assistants.</a></p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/217598/original/file-20180503-153884-17cuab8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/217598/original/file-20180503-153884-17cuab8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/217598/original/file-20180503-153884-17cuab8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/217598/original/file-20180503-153884-17cuab8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/217598/original/file-20180503-153884-17cuab8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/217598/original/file-20180503-153884-17cuab8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/217598/original/file-20180503-153884-17cuab8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A red squirrel is seen in this photo nibbling on a nut. With spring upon us in the Northern Hemisphere, watching wild animals hard at work is a reminder of how we benefit from their labour.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>Along with my endless delight in watching chipmunks stuffing their cheeks to refill their networks of food burrows, as a labour studies scholar, I also recognize that these dynamics are examples of work. </p>
<p>Wild animals work. They work hard.</p>
<p>The idea of work still tends to evoke particular images of manual and blue-collar jobs, but the realities of people’s livelihoods have always been and continue to be much more diverse. This is true for people and animals alike.</p>
<p>Daily life for wild animals involves an elaborate and constant series of tasks and challenges. </p>
<h2>Subsistence work</h2>
<p>Finding food and water. Locating appropriate shelter and protection from the elements, in all seasons. Trying to avoid predators, including humans, our vehicles and our weapons. Navigating landscapes that change dramatically and become even more dangerous with every new road, building and pipeline, not to mention the droughts, floods and other weather events that result from climate change.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/217603/original/file-20180503-153895-6y7kq7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/217603/original/file-20180503-153895-6y7kq7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/217603/original/file-20180503-153895-6y7kq7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/217603/original/file-20180503-153895-6y7kq7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/217603/original/file-20180503-153895-6y7kq7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/217603/original/file-20180503-153895-6y7kq7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/217603/original/file-20180503-153895-6y7kq7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Raccoons and other animals have to negotiate a number of man-made issues as they seek out food and shelter.</span>
<span class="attribution"><span class="source">Erwan Hesr/Unsplash</span></span>
</figcaption>
</figure>
<p>This is subsistence work. This is the work wild animals do to survive.</p>
<p>The dynamics become even more challenging when you add reproduction to the mix. Whether guarding a nest of chicks or a den of cubs, animal parents must be vigilant and highly attuned to myriad sights and sounds. The young must be guarded, fed, comforted and taught. </p>
<p>Young animals are not only taught to survive, they are also taught how to thrive and negotiate the social realities of their species, <a href="https://www.sciencedaily.com/releases/2009/10/091022122321.htm">and often their particular community</a>. This includes the need to understand relationships, social expectations, hierarchies and ways of communicating. This is care work.</p>
<h2>Every animal mother is a working mother</h2>
<p>The slogan “every mother is a working mother” was coined by feminists who wanted to draw attention to essential, and often overlooked and devalued, unpaid domestic labour. </p>
<p>Feminist political economists now use the term <a href="http://www.mqup.ca/social-reproduction-products-9780773531031.php">social reproduction</a> to highlight the countless daily tasks carried out in homes and families, predominantly by women. These tasks ensure the maintenance of whole generations of people — and subsidize every society and economy.</p>
<p>I argue that animals also engage in social reproduction. </p>
<p>Biological reproduction is just the beginning. The effect of animals’ subsistence and care work is the social reproduction of their young, their group and their species.</p>
<p>In fact, I suggest we recognize that wild animals are also integral to what I call eco-social reproduction: The subsistence and care work they do contributes <a href="https://brock.scholarsportal.info/journals/SSJ/article/view/1350/1366">to the maintenance of ecosystems</a>. </p>
<p>For example, <a href="https://www.worldwildlife.org/species/elephant">the World Wildlife Fund points out</a>:</p>
<blockquote>
<p>In tropical forests, elephants create clearings and gaps in the canopy that encourage tree regeneration. In the savannas, they reduce bush cover to create an environment favourable to a mix of browsing and grazing animals. The seeds of many plant species are dependent on passing through an elephant’s digestive tract before they can germinate. It is calculated that at least a third of tree species in central African forests rely on elephants in this way for distribution of seeds.</p>
</blockquote>
<p>In other words, the subsistence and care work elephants do daily in order to survive and raise their young also benefits other species and their ecosystem: It’s a process of eco-social reproduction.</p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/217604/original/file-20180503-153873-tsv263.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/217604/original/file-20180503-153873-tsv263.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/217604/original/file-20180503-153873-tsv263.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/217604/original/file-20180503-153873-tsv263.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/217604/original/file-20180503-153873-tsv263.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/217604/original/file-20180503-153873-tsv263.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/217604/original/file-20180503-153873-tsv263.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A least a third of tree species in Africa are thought to rely on elephants for distributing seeds.</span>
<span class="attribution"><span class="source">Harshil Gudka/Unsplash</span></span>
</figcaption>
</figure>
<p>Creatures great and small contribute to eco-social reproduction through their daily labour. Those chubby-cheeked squirrels and chipmunks? They are also <a href="https://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2745.2010.01716.x">invaluable seed-dispersers</a>.</p>
<p>And humans are directly affected, most obviously by bees and other pollinators whose daily subsistence labour pollinates <a href="https://www.nrdc.org/sites/default/files/bees.pdf">about a third of our food crops.</a></p>
<p>Thinking about wild animals and their actions in this way offers a different perspective on our multi-species communities. If a raccoon leaves a messy mural of orange peels and tea bags on your driveway, you could pause and recognize that she or he is, like you, working to survive and care for loved ones, and perhaps feel some empathy alongside the irritation. </p>
<h2>Start seeing animals differently</h2>
<p>Animals’ dietary choices also result from need rather than greed <a href="https://www.theguardian.com/commentisfree/2017/nov/07/big-meat-big-dairy-carbon-emmissions-exxon-mobil">and, unlike ours, are not fuelling climate change.</a></p>
<p>Recognizing the complexity of the lives of the other species with whom we share this planet can also be part of expanding our webs of compassion and solidarity.</p>
<p>We should broaden our intellectual horizons by integrating Indigenous ways of knowing, the social sciences and scientific approaches, as we pursue deeper knowledge, and, most importantly, more ethical action, including in political and economic arenas.</p>
<p>We have many opportunities to see animals differently and more carefully.</p>
<p>There is an axiom that often circulates about the behaviour of Homo Sapiens: “Humans: We’re not the only species, we just act like it.” Let’s not.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-indigenous-knowledge-advances-modern-science-and-technology-89351">How Indigenous knowledge advances modern science and technology</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/96084/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kendra Coulter receives funding from the Social Sciences and Humanities Research Council of Canada.</span></em></p>Wild animals are hard at work this spring. Here’s how their hard labour benefits humans, and why we should be more appreciative.Kendra Coulter, Associate Professor in Labour Studies and Chancellor's Chair for Research Excellence; Member of the Royal Society of Canada's College of New Scholars, Artists and Scientists, Brock UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/820242017-08-15T14:09:37Z2017-08-15T14:09:37ZWhy red squirrels are thriving in one corner of Merseyside<figure><img src="https://images.theconversation.com/files/182085/original/file-20170815-29205-5bcb20.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption"></span> <span class="attribution"><span class="source">Phil Kieran / shutterstock</span></span></figcaption></figure><p>By 2050, <a href="http://ow.ly/MpUZ30e73sA">two thirds</a> of the world’s population will live in an urban area. Until recently, we knew little about how wild animals were coping with the growth of all those towns and cities. The field of urban wildlife ecology has since emerged to fill this gap.</p>
<p>Urban ecologists have found some species, like Britain’s <a href="http://ow.ly/XkQb30e73IM">hedgehogs</a>, have struggled to cope. But other species, often called “synurbic”, have proven themselves very adaptable and, in some cases, they can actually live at <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1469-7998.2011.00887.x/abstract">higher densities</a> in cities. </p>
<p>One species capable of modern urban living is the red squirrel. Understanding how they behave in towns and cities, a topic that is relatively unexplored, could help their long-term conservation.</p>
<p>Red squirrels are found in cities right across mainland Europe, for example in <a href="http://ow.ly/iaMw30e73WQ">Finland</a>, <a href="http://www.scoiattologrigio.org/scoiattoli%20-%20european%20red%20squirrels%20urban%20park.pdf">France</a>, and <a href="http://ow.ly/20Jp30e746U">Poland</a>. It is likely they were once also found in many UK towns too. However, Britain’s native squirrel is now a very rare sight, thanks to decades of habitat loss and the introduction of the larger and more competitive grey squirrel from North America.</p>
<h2>A red stronghold</h2>
<p>But one town where the reds haven’t disappeared is Formby, in Merseyside, the study site for my PhD researching the urban ecology of red squirrels. Formby is one of few red squirrel strongholds in England and one of the only remaining urban areas where they can be found at all. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"519839175932379136"}"></div></p>
<p>Red squirrels can easily be spotted in gardens throughout the town. Local residents are passionate about protecting their unusual wildlife, with many of them providing supplemental food and volunteering locally with <a href="https://www.wildlifetrusts.org/news/2017/02/24/vital-volunteers-needed-save-our-last-red-squirrels">conservation organisations</a>. These organisations manage the extensive woodland to the west of the town, where they supply additional food themselves, and employ dedicated “squirrel officers” who help maintain “<a href="https://www.lancswt.org.uk/redsquirrels">grey squirrel-free</a>” habitats.</p>
<p>In addition to the woodland, the town itself contains ideal habitat, with hedgerows and trees lining the roads and gardens, which provide corridors for the squirrels to move through. Urban areas also typically have fewer natural predators, such as buzzards.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/182090/original/file-20170815-28964-6ywrrk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/182090/original/file-20170815-28964-6ywrrk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/182090/original/file-20170815-28964-6ywrrk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/182090/original/file-20170815-28964-6ywrrk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/182090/original/file-20170815-28964-6ywrrk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/182090/original/file-20170815-28964-6ywrrk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/182090/original/file-20170815-28964-6ywrrk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/182090/original/file-20170815-28964-6ywrrk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The woods near Formby are famous for their red squirrels.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/fotofrivolity08/13611318394/">Ellie</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Unfortunately, invasive grey squirrels like all these things too and, given the chance, they would colonise the town and displace the reds. However, a combination of grey squirrel control (including protection from their advances on one side by the sea), supplemental feeding, suitable urban green spaces, and careful monitoring by volunteers and rangers have meant that the reds have clung on in Formby, despite greys replacing them elsewhere in the UK. </p>
<p>The longer-term strategy is to manage the area in favour of the reds. This could involve, for example, planting trees which the reds can easily exploit but the greys are less able to, like native conifers and small-seeded broadleaved trees such as birch or ash. Greys instead prefer large-seeded broadleaves, such as oak and beech.</p>
<h2>Urban hazards</h2>
<p>However, there are downsides to living alongside people. For instance, several studies have flagged <a href="http://ow.ly/C6OZ30e74me">road traffic</a> as the biggest cause of squirrel mortality. Despite fewer natural predators, there are higher numbers of pets, such as <a href="http://onlinelibrary.wiley.com/doi/10.1017/S0952836902000134/abstract">cats</a> and dogs, that can injure and even kill squirrels. In addition, some of the trees in the town may be gradually lost as residents landscape their gardens, further fragmenting the remaining habitat.</p>
<p>Even the widespread supplemental feeding could have hidden negative consequences. In Formby, well-meaning residents provide lots of peanuts: one of the squirrels’ favourite foods. Unfortunately, peanuts are low in calcium and alone do not give the required nutrition that a squirrel needs. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/182092/original/file-20170815-28398-1ayvmsu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/182092/original/file-20170815-28398-1ayvmsu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/182092/original/file-20170815-28398-1ayvmsu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/182092/original/file-20170815-28398-1ayvmsu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/182092/original/file-20170815-28398-1ayvmsu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/182092/original/file-20170815-28398-1ayvmsu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/182092/original/file-20170815-28398-1ayvmsu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/182092/original/file-20170815-28398-1ayvmsu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Chomping on a peanut provided by a well-meaning local.</span>
<span class="attribution"><span class="source">Kat Fingland</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>If feeders are not cleaned thoroughly and regularly, this could also contribute to another outbreak of <a href="http://ow.ly/SiNI30e74wz">squirrelpox virus</a> or other diseases. This suggests that residents, who are enthusiastic about feeding the squirrels (and should continue to do so), perhaps need to be provided with more information, such as on what to supply for a varied diet.</p>
<h2>Urban management as a conservation tool</h2>
<p>Much of the research and conservation of red squirrels in the UK is carried out in more rural areas, such as Kielder Forest in Cumbria, often along the interface with the invasive grey squirrel. However, managing urban sites for the benefit of the native reds could be a useful alternative conservation tool, through making the most of the benefits of living alongside people. </p>
<p>For example, local volunteers could act as a free and dedicated workforce for conserving and monitoring the red squirrels, as is the case in Formby. This could be employed in the nearby towns, or even elsewhere in Britain near squirrel strongholds, to hopefully encourage the reds to disperse and reoccupy areas as they become free from greys. This is currently occurring in Wales, with reds crossing over from the island of <a href="https://www.theguardian.com/environment/2016/oct/13/red-squirrels-wales-protected-military-style-strategy-ogwen-valley">Anglesey</a> onto the mainland as rangers remove greys from the area around nearby Bangor.</p>
<p>An urban management plan could also create the opportunity to develop more green spaces and wildlife-friendly gardens. This would benefit all of the local biodiversity, not only squirrels, as well as the people.</p>
<p>This is what my research aims to explore over the next few years: how have red squirrels adapted to urban life, and how do the associated resources and risks affect their ecology. By understanding this, we can hopefully develop a strategy to better protect this charming native species.</p><img src="https://counter.theconversation.com/content/82024/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kathryn Fingland is working closely with the Lancashire Wildlife Trust and National Trust to conduct her PhD research in Formby.</span></em></p>Formby is one of the only remaining urban areas in England where red squirrels can be found at all.Kathryn Fingland, Doctoral Researcher in Wildlife Conservation & Ecology, Nottingham Trent UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/754702017-04-06T14:01:41Z2017-04-06T14:01:41ZGrey squirrels are bad for the British countryside – full stop<figure><img src="https://images.theconversation.com/files/163326/original/image-20170330-4578-1ftx14x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/113551735@N04/21418461706/">Tom D/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>According to some animal rights groups the grey squirrel is a <a href="http://www.huffingtonpost.co.uk/andrew-tyler/red-fur-good-grey-fur-bad_b_10144572.html">victim of circumstance</a>. They say it has been made a <a href="https://www.animalaid.org.uk/please-defend-grey-squirrels/">scapegoat</a> for regional red squirrel population extinctions and claim that loss of the reds is caused entirely <a href="http://www.thejournal.co.uk/news/north-east-news/father-son-champion-grey-squirrels-4468630">coincidentally by habitat change</a>. They suggest the <a href="http://www.grey-squirrel.org.uk/victimising_grey_squirrels_2.pdf">true facts are being hidden</a> and scientific research being <a href="http://www.thepetitionsite.com/en-gb/723/774/674/stop-the-european-union-squirrel-cull/">intentionally misinterpreted</a>. </p>
<p>If so, then this conspiracy must extend to <a href="http://www.telegraph.co.uk/news/earth/wildlife/8331195/What-is-the-law-on-killing-squirrels.html">British legal provisions</a> and <a href="https://www.theguardian.com/environment/2015/sep/25/eu-clamps-down-on-grey-squirrels-and-other-invasive-wildlife">EU directives</a> both listing the grey squirrel as an invader to be controlled, right? </p>
<p>Well, no – put this argument to the test and you’ll see that the facts actually do stack up against the grey squirrel. The reality is that, while the grey squirrel is an important part of <a href="https://cals.arizona.edu/research/redsquirrel/res_pdf/Other%20Squirrel%20and%20Sky%20Island%20Publications/Mamm%20Spec%20Sciurus%20carolinensis%2094.pdf">North American forest ecosystems</a>, since being brought to Europe by the <a href="https://www.theguardian.com/environment/2012/sep/05/red-grey-squirrels-cornwall">Victorians</a> in 1876, the animal has had severe <a href="https://www.woodlandtrust.org.uk/mediafile/100258230/Squirrel-position-statement.pdf">ecological and economic impacts</a> on British woodlands. </p>
<p>Acrobatic and entertaining they may be, but the charge sheet against the grey squirrel is based on hundreds of peer-reviewed research papers. There really is no <a href="https://theconversation.com/in-defence-of-the-grey-squirrel-britains-most-unpopular-invader-73983">defence</a> for it. </p>
<h2>Greys vs red in Europe</h2>
<p>Today there are <a href="http://www.telegraph.co.uk/news/earth/wildlife/10705527/History-of-grey-squirrels-in-UK.html">approximately 2.5m</a> grey squirrels in Britain, but less than <a href="https://www.forestry.gov.uk/forestry/redsquirrel">140,000 reds</a>. Grey squirrels <a href="http://www.snh.org.uk/pdfs/publications/naturallyscottish/redsquirrel.pdf">out-compete</a> native reds for food and space. They also dig up and <a href="https://www.jstor.org/stable/4602061?seq=1#page_scan_tab_contents">consume seed</a> that red squirrels have buried as a winter store. This behaviour reduces red squirrel skeletal growth rates and adult size, and greatly depresses <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2656.2004.00791.x/abstract">juvenile survival rates</a> too. </p>
<p>In addition, greys harbour infections – including <a href="http://www.macs.hw.ac.uk/%7Eawhite/White_Hystrix2016.pdf">squirrel pox</a>, which can devastate red squirrel populations. They <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3914897/">elevate local viral and nematode infection rates</a>, and bring in new parasites, such as <a href="https://air.unimi.it/retrieve/handle/2434/232973/302558/phd_unimi_r08996.pdf">Strongyloides robustus</a>, which are picked up by red squirrels.</p>
<p>Occasionally a healthy red squirrel is found with squirrel pox antibodies – some researchers have suggested that this is evidence of them <a href="https://www.theguardian.com/environment/2013/nov/22/red-squirrels-poxvirus-resistance">evolving resistance</a> to the pox. Unfortunately, 63% of red squirrels dying from pox have also been found to have this <a href="http://squirrelweb.co.uk/2015/06/22/new-book-on-red-squirrel-conservation-published/">antibody response present</a> and there is no evidence that these antibodies confer immunity. Even if they did, research has also shown that antibodies are <a href="http://www.italian-journal-of-mammalogy.it/article/view/10126">gone within 18 months</a> and, irrespective of any resistance, red populations would be replaced by grey via competition anyway.</p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/163328/original/image-20170330-4555-i3vuw7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/163328/original/image-20170330-4555-i3vuw7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/163328/original/image-20170330-4555-i3vuw7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/163328/original/image-20170330-4555-i3vuw7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/163328/original/image-20170330-4555-i3vuw7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/163328/original/image-20170330-4555-i3vuw7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/163328/original/image-20170330-4555-i3vuw7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Squirrel pox.</span>
<span class="attribution"><span class="source">Sarah McNeil</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Woodland damage</h2>
<p>Grey squirrels also <a href="http://www.sciencedirect.com/science/article/pii/S0378112716300421">damage and kill forest trees</a> making it impossible for foresters to grow high-grade hardwood. This means such material is imported instead, bringing with it the risk of <a href="https://www.theguardian.com/environment/2016/oct/23/british-trees-threat-imported-timber-disease-china">new tree pests and pathogens</a>.</p>
<p>Tree damage is most frequently seen on the branches and trunks of oak, beech and maple; <a href="https://www.forestry.gov.uk/fr/infd-7rlgm2">bark is stripped</a> by squirrels eager to consume the <a href="https://www.forestry.gov.uk/pdf/fcpn004.pdf/$FILE/fcpn004.pdf">the sap underneath</a>. Tree stems break or die following stripping, which in turn leads to changes in the <a href="https://www.forestry.gov.uk/pdf/fcpn004.pdf/$FILE/fcpn004.pdf">structure and species composition</a> of high canopy in amenity woodlands.</p>
<p>Even songbirds are affected by grey squirrels. A <a href="http://news.cision.com/kendalls/r/predation-of-woodland-songbirds--grey-squirrels-have-a-case-to-answer,c9224977">recent study gave evidence</a> of negative association between woodland songbird fledging rates and presence of grey squirrels – though it must be noted that this was not observed annually and only seen on some of the sites studied. Earlier studies didn’t find evidence to indicate greys <a href="http://news.bbc.co.uk/earth/hi/earth_news/newsid_8448000/8448807.stm">affect bird population</a>, but also didn’t exclude the possibility – even for bird species whose population is increasing overall. </p>
<p>Other animals may be affected by greys too: there has been some suggestion that squirrels compete with <a href="http://link.springer.com/chapter/10.1007%2F978-94-011-2362-4_11">dormice for hazel nuts</a>, though more research is needed to <a href="http://www.europeansquirrelinitiative.org/wp-content/uploads/2016/12/web-ESI-newsletter-issue-29-lowres.pdf">confirm the true impact</a>.</p>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/163329/original/image-20170330-4557-1auejbp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/163329/original/image-20170330-4557-1auejbp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/163329/original/image-20170330-4557-1auejbp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/163329/original/image-20170330-4557-1auejbp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/163329/original/image-20170330-4557-1auejbp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/163329/original/image-20170330-4557-1auejbp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/163329/original/image-20170330-4557-1auejbp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Stripped tree bark.</span>
<span class="attribution"><span class="source">Craig Shuttleworth</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Controlling greys</h2>
<p>The Wildlife Trust has recently <a href="https://www.theguardian.com/environment/2017/feb/24/red-squirrels-5000-volunteers-sought-to-save-species-and-help-kill-invasive-greys">started to recruit</a> 5,000 volunteers to monitor and control grey squirrel populations. However, a look beyond the headlines will reveal thousands of people are already legally <a href="http://www.smallholder.co.uk/news/15080927.Grey_squirrels_best_controlled_using_a_variety_of_techniques/?ref=mrb&lp=13">trapping and shooting</a> greys across the country to control their numbers. <a href="http://www.northernredsquirrels.org.uk/nrs-groups/">Volunteer groups</a> cull 6,000 grey squirrels per year in the north of England, for example. Even in areas where reds are absent, locals control grey squirrels to protect woodlands or <a href="https://www.gov.uk/pest-control-on-your-property">prevent damage to property</a>. This is not some dramatic new approach by the Wildlife Trust, but is simply reinforcing an established national movement.</p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/163327/original/image-20170330-4551-x7l8rh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/163327/original/image-20170330-4551-x7l8rh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=424&fit=crop&dpr=1 600w, https://images.theconversation.com/files/163327/original/image-20170330-4551-x7l8rh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=424&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/163327/original/image-20170330-4551-x7l8rh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=424&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/163327/original/image-20170330-4551-x7l8rh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=533&fit=crop&dpr=1 754w, https://images.theconversation.com/files/163327/original/image-20170330-4551-x7l8rh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=533&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/163327/original/image-20170330-4551-x7l8rh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=533&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Red and grey meet on the battleground.</span>
<span class="attribution"><span class="source">David Bailey</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The eradication of greys from the <a href="http://link.springer.com/article/10.1007/s10530-014-0671-8">Welsh isle of Anglesey</a> saw red squirrel numbers increase from 40 to 700 and there are other <a href="http://www.italian-journal-of-mammalogy.it/article/view/9988">examples</a> of grey control halting or reversing red squirrel decline. Research has also demonstrated that red squirrels do not prefer <a href="https://www.researchgate.net/publication/279174227_Red_squirrel_population_dynamics_in_different_habitats">conifer to broadleaved</a> habitat and are just as happy in either.</p>
<p>Future control may involve giving the squirrels <a href="https://www.ncbi.nlm.nih.gov/pubmed/22182332">contraception</a>, but will almost certainly not rely solely on this because of logistical barriers. The pine marten may assist in some landscapes too: <a href="http://link.springer.com/article/10.1007/s10531-014-0632-7">one Irish study</a> found a strong negative correlation between pine martens and greys in the woodlands studied. However, the use of trapping and shooting will inevitably continue as part of an <a href="http://www.rfs.org.uk/news/2017/3/grey-squirrel-fertility-control-funding-top-priority-says-rfs/">integrated national approach</a>.</p>
<p>And so the grey squirrel stands guilty as charged. Their presence has decimated the British countryside since they were introduced from North America, and if we do not continue to control the species, the future for red squirrels and woodland ecosystems will be bleak.</p><img src="https://counter.theconversation.com/content/75470/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Craig Shuttleworth is an independent advisor to the European Squirrel Initiative and is on the management board of the EU LIFE14 NAT/UK/000467 invasive species project. He is a Director of Red Squirrels Trust Wales which receives funding from Welsh Government to study viral infections in squirrel species including squirrelpox. </span></em></p>Grey squirrels are wreaking havoc on UK woodlands.Craig Shuttleworth, Honorary Visiting Research Fellow, Bangor UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/739832017-03-08T00:10:57Z2017-03-08T00:10:57ZIn defence of the grey squirrel, Britain’s most unpopular invader<figure><img src="https://images.theconversation.com/files/159869/original/image-20170308-14966-kvh4eq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Jason Gilchrist / jasongilchrist.co.uk</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Furry, fast, occasionally chubby. Small, whiskered, bushy tailed. An expert climber. A nut eater. And grey.</p>
<p>For those in the UK, everything was going great until that last trait. You were probably thinking “cute” and “cuddly”, and feeling positive about this mystery mammal. Until you discover it is the grey and not the red squirrel.</p>
<p>Grey squirrels are a contradiction. They have all the characteristics of animals that people tend to love, and yet they are actively persecuted by humankind. BBC presenter Chris Packham calls them Britain’s “most unpopular non-native invader” – and one of their unflattering nicknames is the “<a href="http://www.dailymail.co.uk/news/article-390805/Damn-tree-rats.html">tree rat</a>”. </p>
<p>The Wildlife Trust has recently announced plans to recruit <a href="https://www.theguardian.com/environment/2017/feb/24/red-squirrels-5000-volunteers-sought-to-save-species-and-help-kill-invasive-greys">an army of 5,000 volunteers</a> to monitor their endangered native relative, the red squirrel – and kill the greys.</p>
<h2>Cute but criminal</h2>
<p>So why such a bad press for grey squirrels? Firstly, they ain’t from around here: greys were deliberately introduced from North America in the late 19th century as an exotic addition to country estates. They soon spread across the UK, however, and today the invaders are the dominant squirrel across almost all of England and Wales and much of Scotland and Ireland.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"835126115362619398"}"></div></p>
<p>But hostility towards invasive animals can’t explain the grey squirrel’s unpopularity – as other non-native species don’t get the same negative attention. The UK’s <a href="http://www.mammal.org.uk/species-hub/uk-mammal-list/">naturalised mammals</a> include the brown hare, the edible dormouse, and sika deer. Even the much-loved rabbit is a <a href="http://www.telegraph.co.uk/news/earth/wildlife/6574709/Mouse-and-rabbits-among-non-native-species.html">Roman import</a>.</p>
<p>Instead, grey squirrels are disliked, by foresters due to the damage that they inflict upon trees, and more generally because of the harm they cause to their native relatives, red squirrels. Studies have shown that <a href="https://link.springer.com/article/10.1007/s00265-001-0446-y">greys can outcompete reds</a> – the two species do not directly fight for resources, it is just that the greys are better at gathering the nuts and berries that both live off. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/159587/original/image-20170306-20749-82nt7q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/159587/original/image-20170306-20749-82nt7q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/159587/original/image-20170306-20749-82nt7q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=354&fit=crop&dpr=1 600w, https://images.theconversation.com/files/159587/original/image-20170306-20749-82nt7q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=354&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/159587/original/image-20170306-20749-82nt7q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=354&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/159587/original/image-20170306-20749-82nt7q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=445&fit=crop&dpr=1 754w, https://images.theconversation.com/files/159587/original/image-20170306-20749-82nt7q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=445&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/159587/original/image-20170306-20749-82nt7q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=445&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Red squirrel: across the UK greys now outnumber these reds by around 17 to 1.</span>
<span class="attribution"><span class="source">Jason Gilchrist/www.jasongilchrist.co.uk</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Grey squirrels are also unknowingly the carrier of a disease, squirrel pox, to which they are immune, but sadly the red is not. For red squirrels, the pox means painful scabs, ulcers and <a href="http://www.northernredsquirrels.org.uk/squirrels/squirrel-pox-virus/">almost certain death</a> (although some are finally <a href="http://www.forestry.gov.uk/pdf/ukrsg_advice_note_E1.pdf/$FILE/ukrsg_advice_note_E1.pdf">developing resistance</a>). The pox itself may actually be the chief “evil immigrant” in this eco-relationship, with the grey squirrel simply moving into vacant habitat following an epidemic among local red squirrels.</p>
<h2>Ethics and welfare of killing</h2>
<p>Whatever the true ecological relationship between red and grey squirrel, the human species has for many years been waging war on the unfortunate invader. Human nature is such that, the moment we label a species as a “pest”, the welfare of individual animals is often ignored. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/159856/original/image-20170307-14934-qg84ga.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/159856/original/image-20170307-14934-qg84ga.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/159856/original/image-20170307-14934-qg84ga.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=367&fit=crop&dpr=1 600w, https://images.theconversation.com/files/159856/original/image-20170307-14934-qg84ga.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=367&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/159856/original/image-20170307-14934-qg84ga.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=367&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/159856/original/image-20170307-14934-qg84ga.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=461&fit=crop&dpr=1 754w, https://images.theconversation.com/files/159856/original/image-20170307-14934-qg84ga.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=461&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/159856/original/image-20170307-14934-qg84ga.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=461&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Watch out! The grey squirrel is under attack.</span>
<span class="attribution"><span class="source">Jason Gilchrist/www.jasongilchrist.co.uk</span></span>
</figcaption>
</figure>
<p>The grey squirrel is not so different from the red. How would we feel if we were to trap, poison and shoot the red squirrel? Greys did not come over here of their own accord and did not ask to be introduced. Neither do they have any control over the pox that they carry. They do what they do; which is to be grey squirrels. In response, what we do, is kill them by the tens of thousands, year after year. The killing is “humane” – but how free of pain and suffering is it for the squirrels? We poison them. We trap them. We shoot them. We bludgeon them to death.</p>
<p>How many dead greys is a live red worth? The success of this sustained massacre is debatable. Nobody seriously believes that the grey squirrel could be exterminated in the UK. A report by Stephen Harris and colleagues at the University of Bristol concluded that culling greys to save reds is <a href="https://www.onekind.scot/wp-content/uploads/0811_grey_squirrel_populations.pdf">neither viable nor economic</a>. Harris has instead suggested that we should move the reds to <a href="http://news.bbc.co.uk/1/hi/sci/tech/5238462.stm">protected islands</a> and let nature take its course on the mainland. We could <a href="http://www.telegraph.co.uk/news/earth/wildlife/11301638/Millions-of-pounds-of-public-money-to-pay-for-grey-squirrel-cull.html">save ourselves a lot of time, money and effort</a> by not persecuting grey squirrels.</p>
<h2>We don’t need to kill to conserve</h2>
<p>I don’t want Britain to lose its native red squirrel. But neither do I take any joy from the thought of the tens of thousands of culled grey squirrels and the <a href="https://www.theguardian.com/environment/2017/feb/24/red-squirrels-5000-volunteers-sought-to-save-species-and-help-kill-invasive-greys">infinite number that we will have to kill</a> if current plans are to continue in perpetuity. </p>
<p>We need to show a bit more respect to this highly successful species and there are alternative options to culling. We could start by managing forests to favour conifers (which reds prefer) over deciduous trees (the grey’s favourite).</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/159585/original/image-20170306-20739-1199mrs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/159585/original/image-20170306-20739-1199mrs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/159585/original/image-20170306-20739-1199mrs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/159585/original/image-20170306-20739-1199mrs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/159585/original/image-20170306-20739-1199mrs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/159585/original/image-20170306-20739-1199mrs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/159585/original/image-20170306-20739-1199mrs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/159585/original/image-20170306-20739-1199mrs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Pine marten: the smaller and more agile red squirrel evolved alongside this predator and may be better at escaping it.</span>
<span class="attribution"><span class="source">Peter Cairns/scotlandbigpicture.com</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The resurgence of the native pine marten could also swing the balance in favour of reds over greys. A conservation success story in itself, these ferret-like predators were recently spotted in England for the first time in more than a century. In areas of Ireland where pine martens are thriving, grey squirrels have <a href="https://www.theguardian.com/environment/2015/jan/30/how-to-eradicate-grey-squirrels-without-firing-a-shot-pine-martens">almost disappeared</a>, allowing reds to reestablish themselves.</p>
<p>The occurrence of <a href="http://www.telegraph.co.uk/news/earth/wildlife/11516777/Squirrel-Nutkin-fights-back-in-battle-against-grey-rivals.html">pox-resistance</a> within some red squirrel populations is also a reason for hope for red over grey. Last but not least is the development of <a href="https://www.theguardian.com/environment/shortcuts/2017/feb/26/grey-squirrels-prince-charles-nutella?CMP=twt_a-environment_b-gdneco">an oral contraceptive for grey squirrels</a> together with plans to bait them using Nutella.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/159874/original/image-20170308-14932-n1fsc6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/159874/original/image-20170308-14932-n1fsc6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/159874/original/image-20170308-14932-n1fsc6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=394&fit=crop&dpr=1 600w, https://images.theconversation.com/files/159874/original/image-20170308-14932-n1fsc6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=394&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/159874/original/image-20170308-14932-n1fsc6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=394&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/159874/original/image-20170308-14932-n1fsc6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=495&fit=crop&dpr=1 754w, https://images.theconversation.com/files/159874/original/image-20170308-14932-n1fsc6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=495&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/159874/original/image-20170308-14932-n1fsc6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=495&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The humane way to reduce grey squirrel numbers.</span>
<span class="attribution"><span class="source">Jason Gilchrist / jasongilchrist.co.uk</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Some would describe the grey squirrel as criminal. Others would describe the way they are treated by humans as criminal. Ultimately, we don’t necessarily need to kill to conserve.</p><img src="https://counter.theconversation.com/content/73983/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jason Gilchrist does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Grey squirrels have lots of attractive characteristics, yet they are actively persecuted by humankind.Jason Gilchrist, Ecologist, Edinburgh Napier UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/684492016-11-10T19:10:02Z2016-11-10T19:10:02ZBritish red squirrels are suffering from an outbreak of medieval leprosy<figure><img src="https://images.theconversation.com/files/145413/original/image-20161110-21844-e010qp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>For many people, leprosy brings to mind Biblical stories of diseased people cast out from society. It’s a condition that today is largely found in developing countries, whereas in other, mostly Western nations it’s a pestilence of the past that was eradicated decades ago. But recent research has shown the disease not only persists in Britain but, perhaps more alarmingly, is also being carried by one of our best loved and most endangered native mammals, the red squirrel.</p>
<p><a href="http://science.sciencemag.org/content/354/6313/702">The study by researchers</a> at the University of Edinburgh and EPFL in Switzerland found red squirrels from England, Scotland and Ireland were infected with leprosy. In particular, a group from Brownsea Island on the south coast of England had a strain of the disease virtually identical to one that infected humans in the middle ages.</p>
<p>So could it be that leprosy was never entirely eradicated from Britain but instead has lingered on in wildlife reservoir hosts in isolated areas? Possibly, but the whole picture is more complex, not least because of the history of the red squirrel in the British Isles. Understanding what’s going on could help us in our efforts to protect and regrow the red squirrel population.</p>
<p><a href="http://www.who.int/topics/leprosy/en/">Leprosy is an infectious disease</a> caused by bacteria that can persist in the body for years without causing symptoms but can eventually lead to skin lesions, eyesight problems and nerve decay. This can cause sufferers to lose the ability to feel pain and so repeatedly damage parts of their body (leading to the myth that leprosy causes limbs to drop off).</p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/145414/original/image-20161110-25070-q4t963.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/145414/original/image-20161110-25070-q4t963.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=900&fit=crop&dpr=1 600w, https://images.theconversation.com/files/145414/original/image-20161110-25070-q4t963.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=900&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/145414/original/image-20161110-25070-q4t963.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=900&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/145414/original/image-20161110-25070-q4t963.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1131&fit=crop&dpr=1 754w, https://images.theconversation.com/files/145414/original/image-20161110-25070-q4t963.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1131&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/145414/original/image-20161110-25070-q4t963.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1131&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Is it safe to come out?</span>
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<p>The disease seems to cause <a href="http://veterinaryrecord.bmj.com/content/177/8/206.2.full">similar symptoms in red squirrels</a>, with individuals commonly exhibiting alopecia, swollen eyes, ears and digits. How serious a problem the leprosy is for British red squirrels has still to be fully investigated, although high numbers of animals sampled in this study tested positive for the disease. Given the plight of the species, which have gone from a population of millions <a href="http://www.rsne.org.uk/threats">to just 120,000</a> in a few centuries, it cannot be good.</p>
<p>The new research, <a href="http://science.sciencemag.org/content/354/6313/702">published in the journal Science</a>, compared genetic sequence data from diseased squirrels with those taken from contemporary human cases from Mexico and the skeletons of leprosy victims from medieval Europe. The results show that the leprosy in the squirrels was caused not only by the classic bacteria <em>Mycobacterium leprae</em> (long thought to be the sole causative agent of leprosy), but also by the more recently discovered <em>Mycobacterium lepromatosis</em>.</p>
<p>The <em>M leprae</em> strain found on Brownsea Island seems to be almost identical to that of medieval victims from England and Europe. This suggests the disease has persisted in British wildlife long after its eradication from the human population. Using genetic analysis, the researchers also showed the British and Irish strains of <em>M lepromatosis</em> had a common ancestor just 200 years ago. By comparison, they separated from the strain found in Mexico 27,000 years ago. This suggests the disease may have actually been imported to Ireland when conservationists first tried to reintroduce red squirrels to the country from Britain <a href="http://www.irelandswildlife.com/history-red-squirrel-ireland/">in the 19th century</a>.</p>
<h2>Isolated from humans</h2>
<p>The reason leprosy has continued in red squirrels while being effectively eradicated from the human population could be the result of the changing nature of our interactions with the animals since the middle ages. Red squirrels are no longer hunted for food or fur but their numbers have <a href="http://www.rsne.org.uk/threats">declined dramatically</a> thanks to habitat destruction, other diseases such as squirrelpox and the spread of grey squirrels. Red squirrels are now largely extinct from their former ranges in England and Wales, with core populations <a href="http://www.snh.gov.uk/about-scotlands-nature/species/mammals/land-mammals/squirrels/">located in Scotland</a>.</p>
<p>This decline means red squirrels are now protected by law in both the UK and Ireland. Legal protection, if implemented properly, limits the amount of contact we have with a species and so can reduce our negative impact on it. But this reduced contact also means we know less about the diseases of that species and so could help explain why the rediscovery of leprosy is such a surprise.</p>
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<img alt="" src="https://images.theconversation.com/files/145416/original/image-20161110-21844-ru7zdf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/145416/original/image-20161110-21844-ru7zdf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/145416/original/image-20161110-21844-ru7zdf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/145416/original/image-20161110-21844-ru7zdf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/145416/original/image-20161110-21844-ru7zdf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/145416/original/image-20161110-21844-ru7zdf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/145416/original/image-20161110-21844-ru7zdf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">As if I didn’t have enough to worry about.</span>
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<p>Humans are a selfish species at heart and so the focus of our fight against disease is generally limited to those pathogens that threaten our own health or our economy. This means we tend to be oblivious to the risks from diseases among species we have limited interaction with.</p>
<p>This is even more likely if we associate the disease with a specific species, especially through its name or our understanding of its history. Over the past 30 years, we have been caught unawares by <a href="https://www.cambridge.org/core/journals/epidemiology-and-infection/article/bovine-tuberculosis-in-southern-african-wildlife-a-multi-species-hostpathogen-system/FDD788BEF42F7A440876622EA90E79ED">bovine tuberculosis in African lions</a>, <a href="http://www.sciencedirect.com/science/article/pii/0378113595000186">canine distemper virus in Siberian seals</a> <a href="http://mbio.asm.org/content/4/4/e00410-13.short">and tigers</a>, and leprosy in <a href="http://www.sciencedirect.com/science/article/pii/S0190962283702069">North American armadillos</a>.</p>
<p>What this latest study shows is that we should be more prepared to expect the unexpected when it comes to disease surveillance. We owe it to ourselves, and the animals we manage, to broaden our horizons and our understanding of disease dynamics in all species.</p>
<p>Comprehensive disease screening would help us reduce the chances of accidentally introducing pathogens into a new species or area when moving animals around for conservation reasons. Better understanding of the disease threats our squirrels face could also help us develop bespoke conservation strategies. For example, we could tailor captive breeding programmes to the levels of genetic diversity needed to bolster natural resistance to disease. Hopefully studies like this will help us secure the long-term future of this charismatic little mammal.</p><img src="https://counter.theconversation.com/content/68449/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Stephen Harrison does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Some have a strain that is almost identical to one that infected humans in the middle ages.Stephen Harrison, Lecturer in Animal Science, Nottingham Trent UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/460512015-08-27T05:37:30Z2015-08-27T05:37:30ZResurgent pine martens could be good news for red squirrels<figure><img src="https://images.theconversation.com/files/92804/original/image-20150824-17760-1811mrl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-301498676/stock-photo-pine-marten-on-log-in-dense-green-foliage-pine-marten-european-pine-marten-martes-martes.html?src=pp-same_artist-297853694-YQHED2pyi-p6PF3VBf8KVA-4">www.shutterstock.com</a></span></figcaption></figure><p>A pine marten has been <a href="http://www.theguardian.com/environment/2015/jul/15/pine-marten-spotted-in-england-for-the-first-time-in-over-100-years">spotted in England recently</a>, the first in more than 100 years. The reemergence of Britain’s second-rarest mammal, a cat-sized relative of badgers and weasels, is a great story in itself. But it may have another upside, as pine martens could be bad news for one of the UK’s least popular animals: the invasive grey squirrel.</p>
<p>Unlike pine martens, grey squirrels are not native to Britain. These North American “aliens” were first introduced in the 1870s and soon made themselves at home. In the UK they are considered an invasive species – their “<a href="http://www.forestry.gov.uk/pdf/fcpn004.pdf/$FILE/fcpn004.pdf">bark-stripping</a>” harms the growth of new woodlands and has a big economic cost. </p>
<p>Grey squirrels’ success has also been to the <a href="http://www.grey-squirrel.org.uk/reds.php">detriment</a> of the native red squirrel. Greys do not kill reds directly, but they do spread <a href="http://www.northernredsquirrels.org.uk/squirrels/squirrel-pox-virus/">squirrel pox</a>, a virus that causes distinctive ulcers on the reds’ eyes and nose, leading to death within a week. Grey squirrels themselves are unaffected – they’ve developed immunity. </p>
<p>Things are looking pretty dire for the UK’s red squirrels. Competition, disease and habitat loss mean that, if current <a href="http://www.rsne.org.uk/grey-squirrel-control">grey squirrel control</a> efforts were to stop, red squirrels would become extinct in Britain.</p>
<p>I’m interested in how pine martens fit into this struggle. Habitat loss, hunting for fur and predator control by game keepers meant they became practically extinct in England and Wales. However in Scotland and Ireland they are making a comeback – and where they are returning, grey squirrels are disappearing.</p>
<h2>Why Ireland has red squirrels</h2>
<p>The impact in Ireland has been particularly notable. A <a href="http://link.springer.com/article/10.1007%2Fs10531-014-0632-7">four-year study</a> I published in 2014 found pine marten recovery in the Irish midlands was linked to such a significant decline in grey squirrel numbers that the once beleaguered red squirrel population was able to recolonise its former range, including woodlands which had been dominated by greys for more than 30 years. </p>
<p>The study provided the first evidence for what foresters and gamekeepers had been saying for years – where pine martens had returned to healthy numbers, grey squirrels had all but disappeared. But in areas with few or no pine martens, grey squirrels persisted at “<a href="http://link.springer.com/article/10.1007%2Fs10531-014-0632-7">invasive</a>” levels. </p>
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<a href="https://images.theconversation.com/files/92790/original/image-20150824-17787-1uq6oy9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/92790/original/image-20150824-17787-1uq6oy9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/92790/original/image-20150824-17787-1uq6oy9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/92790/original/image-20150824-17787-1uq6oy9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/92790/original/image-20150824-17787-1uq6oy9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/92790/original/image-20150824-17787-1uq6oy9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/92790/original/image-20150824-17787-1uq6oy9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/92790/original/image-20150824-17787-1uq6oy9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">This guy ought to be grateful.</span>
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<p>Red squirrels on the other hand have coexisted with pine martens throughout much of Europe for tens of thousands of years. The two species evolved together. While pine martens will very occasionally eat red squirrels, they don’t seem to have a negative impact on population numbers. In fact, in the Irish study, the areas that red squirrels had recolonised naturally were exclusively those with healthy pine marten populations.</p>
<h2>Do pine martens eat grey squirrels?</h2>
<p>We do know that more pine martens in an area means fewer grey squirrels, but we don’t yet know if this is down to direct predation. It does happen though: the first evidence of a pine marten preying on the American grey squirrel was <a href="http://link.springer.com/article/10.1007/s10344-013-0771-2">also recorded in Ireland</a> in 2013, and we are now looking for evidence of this in the Scottish borders too. </p>
<p>Grey squirrels are larger and less agile than red squirrels and typically spend more of their time on the ground, making them an easier prey. However, having a healthy native predator around could also affect grey squirrels in various other ways: they might simply learn to avoid known pine marten areas, or they might spend less time on the ground foraging, leading to reduced fitness. Grey squirrels might even be suffering physiological effects such as <a href="http://beheco.oxfordjournals.org/content/early/2011/10/10/beheco.arr169.full">stress-induced reproductive problems</a>.</p>
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<h2>Pine martens as pest eradicators?</h2>
<p>Ultimately we need to determine whether the pine marten could act as a natural biological control for the grey squirrel in Britain and Ireland.</p>
<p>That’s why I’m now looking at Scotland, where there have been reports of <a href="http://www.telegraph.co.uk/news/earth/wildlife/10998856/Red-squirrels-are-fighting-back-against-the-greys-experts-claim.html">grey squirrel declines</a> after pine marten recolonisation since the early 2000s. I want to know if the two processes are linked. </p>
<p>There are several subtle but potentially important differences between pine marten populations in the two countries that I’ll need to take into account – Scottish pine martens can feast on field voles, for instance, a rich food source that isn’t found in Ireland.</p>
<p>Mass reintroduction of pine martens may be implausible but the creatures are moving south through Scotland and are literally just a few miles from the English border, so the process of natural recolonisation in England is almost underway. The recent sightings in Shropshire may even mean the remnant Welsh population is spreading into England too. It is important to remember pine martens are very slow breeders however, and it will take the recovering population quite some time to reach levels healthy enough to potentially impact on grey squirrel populations. </p>
<p>Predators are a vital part of a healthy ecosystem and predator prey interactions have an important function. What’s happening in Ireland and potentially Britain with squirrels and pine martens is a great example of how restoring natural predators can reduce the damage caused by invasive species. We are currently living in an unnaturally predator-poor environment, and it’s possible this has allowed some introduced species to reach “invasive” levels, which has ultimately wreaked havoc on our ecosystem. </p>
<p>Interaction between pine martens and squirrels is fascinating from a scientific point of view and we still have lots to learn. But you don’t have to be an ecologist to appreciate the value of promoting one of Britain’s most beautiful native species in order to preserve another.</p><img src="https://counter.theconversation.com/content/46051/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Emma Sheehy receives funding from The Irish Research Council, Marie Curie, Forestry Commission Scotland</span></em></p>Grey squirrels hate these reclusive, cat-sized predators.Emma Sheehy, Postdoctoral Research Fellow in Ecology, University of AberdeenLicensed as Creative Commons – attribution, no derivatives.