tag:theconversation.com,2011:/ca/topics/feral-7300/articlesFeral – The Conversation2023-02-17T03:38:25Ztag:theconversation.com,2011:article/1998672023-02-17T03:38:25Z2023-02-17T03:38:25ZDead kangaroos make a surprising feast for possums in the Australian Alps<figure><img src="https://images.theconversation.com/files/510757/original/file-20230217-28-n3s0iu.JPG?ixlib=rb-1.1.0&rect=33%2C52%2C2002%2C1394&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Brushtail possums were caught on camera eating the flesh of a dead kangaroo.</span> <span class="attribution"><span class="source">James Vandersteen/University of Sydney</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Vultures, hyenas, and Tasmanian devils are highly efficient scavengers, able to locate and consume carrion rapidly, including the meat and bones. </p>
<p>When we think of scavengers, these large carnivores are what comes to mind – not brushtail possums.</p>
<p>So it came as a surprise when these Australian marsupials turned out to be one of the most common scavengers we caught on camera in our <a href="https://www.publish.csiro.au/wr/Fulltext/WR22100">new study published online this month in Wildlife Research</a>. </p>
<h2>Circle of life</h2>
<p>No vertebrate Australian animals survive exclusively by scavenging – for our wildlife, carcasses are a “<a href="https://onlinelibrary.wiley.com/doi/full/10.1111/ddi.13390">sometimes food</a>”.</p>
<p>Scavengers play an important role as ecosystem cleaners, helping to remove carcasses from our landscapes by eating them.</p>
<p>With this in mind, we wanted to know how different seasons affect the use of carcasses by vertebrate scavengers in Kosciuszko National Park, south-east NSW, in the Australian Alps. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/510756/original/file-20230217-14-gm9qj0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="panorama from a mountaintop of other snow-capped, wide mountain ranges below a cloudy sky" src="https://images.theconversation.com/files/510756/original/file-20230217-14-gm9qj0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/510756/original/file-20230217-14-gm9qj0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=235&fit=crop&dpr=1 600w, https://images.theconversation.com/files/510756/original/file-20230217-14-gm9qj0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=235&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/510756/original/file-20230217-14-gm9qj0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=235&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/510756/original/file-20230217-14-gm9qj0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=296&fit=crop&dpr=1 754w, https://images.theconversation.com/files/510756/original/file-20230217-14-gm9qj0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=296&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/510756/original/file-20230217-14-gm9qj0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=296&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Mount Howitt, Victoria, is a part of the Australian Alps and experiences a wide range of temperatures.</span>
<span class="attribution"><span class="source">Loco Photography/Shutterstock</span></span>
</figcaption>
</figure>
<p>Winter in the Australian Alps covers much of the landscape in snow. But by the following summer, that same landscape can warm up considerably and even experience intense <a href="https://bioone.org/journals/Mountain-Research-and-Development/volume-23/issue-3/0276-4741(2003)023%5B0294:ABROTA%5D2.0.CO;2/A-Brief-Report-on-the-2003-Australian-Alps-Bushfires/10.1659/0276-4741(2003)023%5B0294:ABROTA%5D2.0.CO;2.full">bushfires</a>. </p>
<p>We found scavenging was highly seasonal in terms of who visits carcasses throughout the course of a year. Most surprisingly, brushtail possums and ravens drove these seasonal trends, as the most common scavengers recorded, with possums mostly scavenging in winter, and ravens in spring. </p>
<p>These findings emphasised the key role of smaller scavenger species, and uncovered novel insights into the feeding habits of the brushtail possum, which is generally considered to eat mostly plants and insects. </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/DS4EDaoZy18?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
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<h2>Catching possums in the act</h2>
<p>We expected to see different scavengers appearing with each season, so our monitoring ran across the course of a full year from March 2020 till March 2021. </p>
<p>Each consecutive season (starting in autumn, then winter, spring, and summer) we placed 15 fresh eastern grey kangaroo carcasses – sourced from local culls – throughout the alpine environment (60 carcasses total). </p>
<p>Each of these carcasses were monitored by a remote camera for 60 days to record every species that visited, whether that be to investigate or feed on the carcass. </p>
<p>Across 745,599 remote camera images, the scavenger species we recorded were spotted-tail quolls, feral cats, dingoes, pied currawongs, wedge-tailed eagles, brushtail possums, ravens, red foxes, and feral pigs. </p>
<p>Of the scavenging we recorded, 88% was done by brushtail possums and ravens. </p>
<figure class="align-center ">
<img alt="A 3 by 3 grid of photos of animals taken by remote capture. In each photo, the animal is visiting/scavenging on kangaroo carcass." src="https://images.theconversation.com/files/510765/original/file-20230217-18-ugmd4u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/510765/original/file-20230217-18-ugmd4u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=421&fit=crop&dpr=1 600w, https://images.theconversation.com/files/510765/original/file-20230217-18-ugmd4u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=421&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/510765/original/file-20230217-18-ugmd4u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=421&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/510765/original/file-20230217-18-ugmd4u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=529&fit=crop&dpr=1 754w, https://images.theconversation.com/files/510765/original/file-20230217-18-ugmd4u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=529&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/510765/original/file-20230217-18-ugmd4u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=529&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Our remote camera captured a range of scavengers in the Australian Alps: a) spotted-tail quoll, b) feral cat, c) dingo, d) pied currawong, e) wedge-tailed eagle, f) brushtail possum, g) raven species, h) red fox and i) feral pig.</span>
<span class="attribution"><span class="source">James Vandersteen/University of Sydney</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Surviving the seasons</h2>
<p>We expected the time it would take the scavengers to find – and subsequently scavenge – a carcass would be linked to the smelliness of the carcass. </p>
<p>During summer, we thought, that heat would make the carcasses’ odours more pungent, and therefore easier to find. </p>
<p>We were wrong about that, not in terms of the smell, but how quickly vertebrate scavengers would find the carcasses. </p>
<p>It actually took vertebrate scavengers longer to find the carcasses in the summer, whether for investigation or scavenging. In the winter, carcass visits peaked.</p>
<p>But, we have a potential explanation for this. </p>
<p>In the summer, a carcass is colonised by many scavenging insects within minutes of its death. These “mini scavengers” may have sped up carcass decomposition so much, that vertebrate scavengers had little time to find the fresh carcasses. </p>
<p>Scavenging rates might also have been lowest in the summer because other food sources were abundant.</p>
<p>Brushtail possums, for instance, eat mostly leaves, flowers, fruit and insects, most of which are only seasonally available during summer. </p>
<p>In the winter, when these food sources are scarce, brushtail possums accounted for 81% of all recorded scavenging. They were eating carrion three times more often than during summer. </p>
<figure class="align-center ">
<img alt="A brushtail possum in the snow at night, rearing up next to a kangaroo carcass" src="https://images.theconversation.com/files/510775/original/file-20230217-14-kwzkku.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/510775/original/file-20230217-14-kwzkku.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/510775/original/file-20230217-14-kwzkku.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/510775/original/file-20230217-14-kwzkku.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/510775/original/file-20230217-14-kwzkku.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/510775/original/file-20230217-14-kwzkku.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/510775/original/file-20230217-14-kwzkku.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 brushtail possum braving the cold to ‘protect’ its kangaroo carcass.</span>
<span class="attribution"><span class="source">James Vandersteen/University of Sydney</span></span>
</figcaption>
</figure>
<h2>Feeding the family</h2>
<p>We also considered that the scavengers’ breeding seasons might have an impact on their scavenging rates and behaviours. </p>
<p><a href="https://www.publish.csiro.au/WR/WR15039">Ravens breed</a> from late winter into early spring, and initially prioritise nest construction.</p>
<p>This was even captured by our remote cameras, where ravens were observed collecting fur from the kangaroo carcasses, presumably for nest construction. </p>
<figure class="align-center ">
<img alt="Ravens stand around a kangaroo carcass in the snow, with tufts of kangaroo fur in their beaks" src="https://images.theconversation.com/files/510769/original/file-20230217-18-2z5hy5.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/510769/original/file-20230217-18-2z5hy5.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=421&fit=crop&dpr=1 600w, https://images.theconversation.com/files/510769/original/file-20230217-18-2z5hy5.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=421&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/510769/original/file-20230217-18-2z5hy5.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=421&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/510769/original/file-20230217-18-2z5hy5.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=529&fit=crop&dpr=1 754w, https://images.theconversation.com/files/510769/original/file-20230217-18-2z5hy5.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=529&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/510769/original/file-20230217-18-2z5hy5.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=529&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">This breeding pair of ravens decided that kangaroo fur would make comfy nesting material.</span>
<span class="attribution"><span class="source">James Vandersteen/University of Sydney</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Following nest construction, chick rearing often requires breeding pairs to divide time between foraging, feeding chicks, and protecting the nest. </p>
<p>Inherently, during this time, ravens require more energy and must supplement their diets with lots of high-energy food, <a href="https://www.researchgate.net/publication/241692417_The_scavenging_behaviour_of_the_Australian_Raven_Corvus_coronoides_Patterns_and_influencing_factors">such as carrion</a>.</p>
<p>Of all the raven scavenging we recorded, 67% was done during spring. This suggests ravens rely heavily on carrion to supplement their own diet – and that of their chicks – during their breeding season. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/VdqlTQUkt0E?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<h2>Where were the usual suspects?</h2>
<p>It was also clear that the larger species (dingoes, wedge-tail eagles, feral pigs) were scarcely recorded at the carcass sites. Low rates of scavenging by these larger animals could be another reason why the smaller scavengers were so common.</p>
<p>This is because larger scavengers can scare away or predate on smaller scavengers, potentially moving them away from carcasses. Larger scavengers also have bigger appetites, so in their absence, there was potentially more carrion for smaller species to find.</p>
<p>Although we do not have a good estimate of the true density of larger scavengers in the surrounding environment, species like the dingo are subject to control in the broader region, potentially limiting their numbers. </p>
<figure class="align-center ">
<img alt="A brindle coat dingo stands in an Australian alpine bushland in front of a kangaroo carcass, looking at the camera, licking its lips." src="https://images.theconversation.com/files/510760/original/file-20230217-964-xwkv53.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/510760/original/file-20230217-964-xwkv53.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/510760/original/file-20230217-964-xwkv53.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/510760/original/file-20230217-964-xwkv53.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/510760/original/file-20230217-964-xwkv53.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/510760/original/file-20230217-964-xwkv53.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/510760/original/file-20230217-964-xwkv53.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">We expected to see dingos scavenging. This one seems to have noticed the camera.</span>
<span class="attribution"><span class="source">James Vandersteen/University of Sydney</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Beyond the mountains</h2>
<p>Given the extent of culling operations in Australia targeting overabundant native species (like kangaroos) or pests such as deer and horses, not to mention all the road-kill, it is important to understand what is happening to carcasses in the landscape. </p>
<p>Our study has set a baseline for scavenging dynamics in an alpine ecosystem, and our methods could be used to learn more about the ecology of scavenging in many different environments. </p>
<p>In this case, it was (surprisingly) brushtail possums who appear to be taking advantage of carcasses as a source of food in the Australian Alps.</p><img src="https://counter.theconversation.com/content/199867/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>This work was funded by the Australian Alps National Parks Cooperative Management Program.
James Vandersteen undertook this work as an MPhil student at The University of Sydney. He is, however, currently affiliated with The University of New South Wales as a PhD student.</span></em></p><p class="fine-print"><em><span>This work was funded by the Australian Alps National Parks Co-operative Management Program. Funding/support for related work in the study region has been received from the Australian Pacific Science Foundation, Hermon Slade Foundation, Australian Government, NSW Government (South East Local Land Services, NSW National Parks/NSW Environment Trust), and Australian Geographic. Thomas Newsome is a Council member of the Royal Zoological Society of New South Wales, a member of the Australian Mammal Society and Ecological Society of Australia, and President of the Australasian Wildlife Management Society. </span></em></p>When they set up remote cameras throughout the bush, scientists were not expecting to capture these small marsupials scavenging for flesh.James Vandersteen, PhD Student, UNSW SydneyThomas Newsome, Senior lecturer, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/794282017-07-13T04:11:54Z2017-07-13T04:11:54ZAre Australia’s native pigeons sitting ducks?<figure><img src="https://images.theconversation.com/files/174343/original/file-20170619-32085-pbtl7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">These migratory pied imperial-pigeons in Far North Queensland, like many of Australia's 22 species of native pigeons and doves, play an important role in our ecosystems but may be at risk from emerging viruses in domestic pigeons.</span> <span class="attribution"><span class="source">Dejan Stojanovic</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>The word “pigeon” evokes thoughts of gentle cooing, fluttering in rafters, and poo-encrusted statues. The species responsible for the encrustation is deeply familiar to us, having ridden waves of European expansionism to inhabit every continent, including Australia. First domesticated thousands of years ago, urban pigeons have turned feral again. </p>
<p>Less familiar are the native species that are not your stereotypical pigeons: a posse of pointy-headed crested pigeons in a suburban park, or a flock of topknot pigeons feeding in a camphor laurel. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/174335/original/file-20170619-28805-116d2k5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/174335/original/file-20170619-28805-116d2k5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/174335/original/file-20170619-28805-116d2k5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=200&fit=crop&dpr=1 600w, https://images.theconversation.com/files/174335/original/file-20170619-28805-116d2k5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=200&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/174335/original/file-20170619-28805-116d2k5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=200&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/174335/original/file-20170619-28805-116d2k5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=251&fit=crop&dpr=1 754w, https://images.theconversation.com/files/174335/original/file-20170619-28805-116d2k5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=251&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/174335/original/file-20170619-28805-116d2k5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=251&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Crested pigeons (left), brush bronzewings (centre) and pied imperial-pigeons (right) are amongst the 22 species of native pigeons and doves in Australia. Their charm and beauty belies the important functions they play in ecosystems.</span>
<span class="attribution"><span class="source">Author provided</span></span>
</figcaption>
</figure>
<p>Australia and its neighbouring islands are the global epicentre of pigeon and dove (or “columbid”) diversity with <a href="http://www.iucnredlist.org">the highest density of different columbids – an impressive 134 species – found in the region</a>. Twenty-two of these native species are found in Australia alone, <a href="http://bie.ala.org.au/species/urn:lsid:biodiversity.org.au:afd.taxon:08371787-659c-4546-b4db-b5d6b82eb391">in just about every habitat</a>. </p>
<p>These native species play an important role in ecosystem functioning: they forage for and disperse seeds, concentrate nutrients in the environment, and are a source of food for predators. Fruit doves for example, are zealous fruitarians, and <a href="http://onlinelibrary.wiley.com/doi/10.1002/9781444300321.ch16/summary">the region’s tropical rainforests depend on them for tree diversity</a>. Where <a href="http://onlinelibrary.wiley.com/doi/10.1046/j.1365-2699.2002.00718.x/full">fruit-doves have disappeared in the South Pacific</a>, numerous plant species have lost an effective dispersal mechanism.</p>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/174828/original/file-20170621-2627-vst3ab.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/174828/original/file-20170621-2627-vst3ab.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=638&fit=crop&dpr=1 600w, https://images.theconversation.com/files/174828/original/file-20170621-2627-vst3ab.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=638&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/174828/original/file-20170621-2627-vst3ab.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=638&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/174828/original/file-20170621-2627-vst3ab.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=801&fit=crop&dpr=1 754w, https://images.theconversation.com/files/174828/original/file-20170621-2627-vst3ab.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=801&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/174828/original/file-20170621-2627-vst3ab.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=801&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The rose-crowned fruit-dove is not only beautiful but also plays an important role in dispersing seeds in Australian rainforests.</span>
<span class="attribution"><span class="source">Author provided</span></span>
</figcaption>
</figure>
<p>The future of Australia’s native pigeons however, may depend on our domestic pigeons. Australia’s domestic pigeon population — both feral and captive - is large and interconnected by frequent local and interstate movements. Pigeon racing, for example, involves releasing captive birds hundreds of kilometres from their homes only so they may find their way back. While most birds do navigate home, up to 20% will not return, <a href="http://www.sciencedirect.com/science/article/pii/S0960982211014588">of which some will join feral pigeon populations</a>. Birds are also <a href="http://agriculture.vic.gov.au/agriculture/livestock/interstate-livestock-movements">traded across the country</a> and <a href="http://www.abc.net.au/news/2012-11-17/exotic-bird-trade-going-unchecked/4376888">illegally from overseas</a>. These movements, together with poor biosecurity practices, mean that captive pigeons can and do mingle with feral domestic pigeons.</p>
<p>And here’s a paradox. Could Australia’s feral domestic pigeons become the vector for a dramatic decline of columbids – native species on which Australian ecosystems rely?</p>
<h2>Emerging viral epidemics</h2>
<p>In recent years, two notable infectious diseases have been found to affect our captive domestic pigeons: the <a href="http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0005/408146/Pigeon-paramyxovirus-PPMV1.pdf">pigeon paramyxovirus type 1</a> (PPMV1) and a new strain of the <a href="http://www.dpi.nsw.gov.au/animals-and-livestock/poultry-and-birds/health-disease/rotavirus-pigeon-disease/pigeon-rotavirus-communique-13-february-2017">pigeon rotavirus</a> (G18P). These diseases are notable because in captive domestic flocks they are both spectacularly lethal and difficult to control. </p>
<p>PPMV1, although likely to have <a href="https://invasives.org.au/wp-content/uploads/2014/09/sub74Rev_Att-2-ISC.pdf">originated overseas</a>, is now endemic in Australia. This virus has jumped from captive to feral domestic pigeon populations on several occasions, but fortunately has yet to establish in feral populations.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/174337/original/file-20170619-32085-fqk830.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/174337/original/file-20170619-32085-fqk830.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/174337/original/file-20170619-32085-fqk830.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/174337/original/file-20170619-32085-fqk830.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/174337/original/file-20170619-32085-fqk830.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/174337/original/file-20170619-32085-fqk830.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/174337/original/file-20170619-32085-fqk830.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/174337/original/file-20170619-32085-fqk830.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">Domestic pigeons suffer high mortality rates after being infected with either pigeon paramyxovirus ‘PPMV1’ or pigeon rotavirus ‘G18P’.</span>
<span class="attribution"><span class="source">Dr Colin Walker</span></span>
</figcaption>
</figure>
<p>G18P is thought to have spread to Victoria and South Australia <a href="http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0004/698377/biosecurity-bulletin-rotavirus-pigeon-disease.pdf">from a bird auction in Perth in 2016</a>. PPMV1 also <a href="http://www.dpi.nsw.gov.au/animals-and-livestock/poultry-and-birds/health-disease/advice-for-bird-owners">spread rapidly to multiple states following its first appearance in Melbourne in 2011</a>.</p>
<p>The movements of captive pigeons, and their contact with their feral counterparts, can be the route through which virulent and lethal diseases – such as the PPMV1 and the G18P – may spread to Australia’s native columbids.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/174650/original/file-20170620-24871-11xeq9v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/174650/original/file-20170620-24871-11xeq9v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/174650/original/file-20170620-24871-11xeq9v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=301&fit=crop&dpr=1 600w, https://images.theconversation.com/files/174650/original/file-20170620-24871-11xeq9v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=301&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/174650/original/file-20170620-24871-11xeq9v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=301&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/174650/original/file-20170620-24871-11xeq9v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=378&fit=crop&dpr=1 754w, https://images.theconversation.com/files/174650/original/file-20170620-24871-11xeq9v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=378&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/174650/original/file-20170620-24871-11xeq9v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=378&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Pigeon paramyxovirus and pigeon rotavirus are known to have escaped from captive domestic pigeons into feral domestic pigeons (black arrow). The risk is that these viruses will establish in feral pigeon populations and cause epidemics in our diverse and ecologically important wild native columbids (red arrow).</span>
<span class="attribution"><span class="source">Author provided</span></span>
</figcaption>
</figure>
<h2>What have we got to lose?</h2>
<p>Fortunately, neither PPMV1 nor G18P has crossed over to Australia’s native columbids. We can’t say how likely this is, or how serious the consequences would be, because we have not previously observed such viral infections among our native pigeons. </p>
<p>If the viruses prove equally lethal to native columbids as they are to domestic pigeons, we could see catastrophic population declines across numerous columbid species in Australia over a short period of time.</p>
<p>Should these viruses spread (via feral domestic pigeons), the control and containment of losses among our native pigeon species would be near impossible. Such a nightmare scenario can only be avoided by predicting if and how these viruses might “spill over” into wild columbids so that we can prevent this in the first place.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/174339/original/file-20170619-28797-1ae82id.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/174339/original/file-20170619-28797-1ae82id.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/174339/original/file-20170619-28797-1ae82id.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=240&fit=crop&dpr=1 600w, https://images.theconversation.com/files/174339/original/file-20170619-28797-1ae82id.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=240&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/174339/original/file-20170619-28797-1ae82id.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=240&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/174339/original/file-20170619-28797-1ae82id.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=302&fit=crop&dpr=1 754w, https://images.theconversation.com/files/174339/original/file-20170619-28797-1ae82id.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=302&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/174339/original/file-20170619-28797-1ae82id.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=302&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Maps of Australia showing the overlapping distribution of our 22 native pigeon and dove species (left) and the distribution (in orange) and verified individual records (red dots) of introduced feral domestic pigeons (right).</span>
<span class="attribution"><span class="source">Atlas of Living Australia, Birdlife International</span></span>
</figcaption>
</figure>
<h2>Protecting our pigeons</h2>
<p>Agricultural poultry is routinely screened to check their vulnerability to threats like the PPMV1 and G18P. Such screening is an appropriate response to protect our agricultural industry. </p>
<p>For our native pigeons and doves however, no such similar testing is planned. Based on progress in <a href="http://www.sciencedirect.com/science/article/pii/S0168170211000414">veterinary vaccine development</a> and <a href="https://www.ala-schweiz.ch/images/stories/pdf/ob/2003_100/OrnitholBeob_2003_100_33_Haag-Wackernagel.pdf">advancements in understanding of feral pigeon control</a>, the knowledge and technology required to mitigate this threat should be relatively inexpensive. The threat for these species can be actively managed, now, by improving our biosecurity and vaccination programs for captive domestic pigeons, and eradicating feral domestic pigeons. </p>
<p>The protection of our native columbids however, ultimately relies on valuing their ecosystem functions in the first place.</p><img src="https://counter.theconversation.com/content/79428/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrew Peters works for Charles Sturt University. He has received funding from the former Wildlife Exotic Disease Preparedness Program, Department of Agriculture, Fisheries and Forestry. He is affiliated with the Wildlife Disease Association and Wildlife Health Australia. </span></em></p>Two recently emerging viruses in domestic pigeons in Australia may pose a significant threat to Australia’s 22 species of native pigeons and doves, many of which have crucial ecosystem roles.Andrew Peters, Senior Lecturer in Veterinary Pathology, Charles Sturt UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/593382016-05-24T09:55:09Z2016-05-24T09:55:09ZReal-life jungle books – how feral children raised by animals continue to fire the imagination<p>I recently became a first-time mother. In addition to my daughter, Myrtle, I share my home with a motley collection of rescued animals including dogs, cats, horses, chickens and pigs. This multi-species, multi-generational co-habitation – along with the release of a new adaptation <a href="http://gb.imdb.com/title/tt3040964/">of Rudyard Kipling’s The Jungle Book</a> – left me thinking about the phenomena of feral children, a topic I had considered in <a href="http://www.plutobooks.com/display.asp?K=9780745331195">my book</a> about human-animal interactions more generally. Certainly in some exceptional circumstances I can now appreciate how it might be possible for a human child to be cared for by a non-human surrogate.</p>
<p>In Kipling’s original The Jungle Book, published in 1894, the “man-cub” Mowgli is taken in by a wolf pack after he is separated from his human parents by Shere Kahn, the tiger. The choice of wolves as parental stand-ins for the lost human toddler is arguably more plausible than him being taken in by the Indian rock python Kaa, who, contrary to portrayal on screen as a villain, is one of Mowgli’s friends and mentors in the book – although there are some documented cases of <a href="http://www.dailymail.co.uk/news/article-496990/Meet-snake-boy-best-friends-metre-long-python.html">children being befriended by benevolent pythons</a>.</p>
<p>The canidae family, which include wolves, dogs, and foxes, are the classic surrogate carers for feral human children, featuring regularly in mythological as well as historical and ethnographic accounts. The alleged ability of these animals to raise human children has ancient antecedents in the legends surrounding the foundation of Rome when twins Romulus and Remus were suckled by a she-wolf. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/122469/original/image-20160513-10697-1igb08j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/122469/original/image-20160513-10697-1igb08j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/122469/original/image-20160513-10697-1igb08j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/122469/original/image-20160513-10697-1igb08j.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/122469/original/image-20160513-10697-1igb08j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/122469/original/image-20160513-10697-1igb08j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/122469/original/image-20160513-10697-1igb08j.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">Wolf beginnings: Romulus and Remus, founders of Rome.</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-4294591/stock-photo-she-wolf-breast-feed-romulus-and-remus-place-of-foundation-of-rome.html?src=sSxCSFhCFpO5VwKnKeOP7Q-1-1">Shutterstock</a></span>
</figcaption>
</figure>
<p>Throughout history, accounts of so-called “feral children” have captivated the attention of public and academic audiences alike. The “<a href="http://www.midnapore.in/wolf-children-of-midnapore/wolf-children-of-midnapore1.html">wolf children of Midnapore</a>” is a particularly well-known historical case, where two young girls were found living with a she-wolf and her cubs. The girls did not speak (but howled), moved on all fours, and when they were taken to a local orphanage, preferred the company of the resident dogs to the other children. The persistence of isolated but <a href="http://www.bbc.com/culture/story/20151012-feral-the-children-raised-by-wolves">documented instances of humans</a> raised by or alongside animals continues to fuel our interest. </p>
<p>Take <a href="http://www.theguardian.com/world/1999/oct/10/euanferguson.theobserver">John Ssebunya</a> who, as a three-year-old child in Uganda in 1988, ran away from home after witnessing his father murder his mother. Ssebunya was “adopted” by a troop of vervet monkeys and taught by them how to forage. What makes his story different from many of the other accounts is the fact that he had some human socialisation prior to his incorporation into a non-human social group, and was able to communicate his experiences on his reincorporation into “humanity”. </p>
<h2>Social creatures</h2>
<p>Like primates, wolves and dogs are highly social and all members of the pack will participate in the care of puppies or cubs. Wolves can also enter into friendships with animals who would, in other contexts, represent appropriate prey. An example dating back to 2007 but which did the rounds on social media recently told the story of an unlikely friendship which developed between <a href="http://www.onegreenplanet.org/animalsandnature/donkey-and-wold-best-friends/">a captive wolf and the decrepit donkey</a> who was introduced into the enclosure as live prey. According to some of the people involved in rescuing the pair from their incarceration, the wolf was terrified and the donkey had taken on the role of protector.</p>
<p>In The Jungle Book stories, Mowgli is taught about how to survive in the wild by Baloo, the bear, and Bagheera, the leopard. While such a trio might seem unlikely friends, again there are examples of similar cross-species friendships. For example, the case of a <a href="http://channel.nationalgeographic.com/wild/unlikely-animal-friends/videos/the-lioness-and-the-oryx/">lioness at the Lewa</a> wildlife reserve in Kenya who has repeatedly “adopted” Oryx calves over a period of several years. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/ugi4x8kZJzk?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>Another arresting example, documented by wildlife filmmakers Dereck and Beverly Joubert (above), was the leopardess who they named Legadema, and her cub. After <a href="http://voices.nationalgeographic.com/2014/04/03/baby-baboons-dramatic-encounter-with-lions-ends-with-a-heroic-twist/">Legadema’s first baboon kill</a> a small baby baboon was left attached to the dead body of its mother. Rather than killing it or ignoring it to eat her meal, Legadema picked up the infant when it reached out to her and carried it up a tree where she groomed it, carrying it higher each time it cried. The pair eventually curled up together and slept, but the baby died in the night and it was only then that Legadema returned to the mother baboon’s body to eat. </p>
<p>Such examples might be dismissed as the exceptions that prove the rule and we don’t know what would have happened in the long term. However, there is a clear and well documented case of inter-species adoption, <a href="http://www.ncbi.nlm.nih.gov/pubmed/16786521">by primatologists</a>, in which a baby marmoset was taken in and cared for into adulthood by a group of wild (but provisioned) capuchins.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/123065/original/image-20160518-5867-l5gpw9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/123065/original/image-20160518-5867-l5gpw9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/123065/original/image-20160518-5867-l5gpw9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/123065/original/image-20160518-5867-l5gpw9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/123065/original/image-20160518-5867-l5gpw9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/123065/original/image-20160518-5867-l5gpw9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/123065/original/image-20160518-5867-l5gpw9.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">Capuchins have been known to adopt.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/inottawa/3361791009/in/photolist-6854kX-oA6kBf-9gRvBq-7bV7qD-9rqb5K-9gNbzH-mbPa6e-2TPwdz-qcvNwE-tKMshp-2TTV8w-666PDP-65vUTC-9sXBsK-5RStTn-9gNiue-e8qmAt-e1AMJX-6ZeK2w-5n9Nyv-u3eXv2-6tgqaa-qtUx8p-9gRnpS-8YLA1c-9gR9o7-71hM6g-u2SY95-cAbS4w-5Rzcms-bANxEo-5Jc7vg-oA6U3z-5JggCY-t6dZ8S-8dngyx-64JNLq-BHmUos-tKM5Mv-CYstu-edHWHL-d8g71G-6gwVsm-tKDxi1-qu5pTD-caqAjh-7sDXDC-fCKAtC-okgzDk-oDvu5e">Sang Trinh/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>The ability (or even inclination) to (attempt to) raise the young of another species suggests the possibility of inter-species communication and empathy. Legadema might just have been responding to an innate maternal instinct. But the fact that she engaged with the baboon as a “baby” as opposed to a potential food source was the result of some form of mutual understanding between them; the baby reached out to her, and she responded to its request for comfort. </p>
<p>A final case which brings us back to human children and canines was documented in 2015. A malnourished and neglected two-year-old child was found by authorities in Chile being <a href="http://www.independent.co.uk/news/world/americas/malnourished-two-year-old-found-being-breast-fed-by-dog-in-chile-10487943.html">breastfed by a neighbour’s dog</a>. </p>
<p>Stories of feral children are widely disputed by academics and are also seen as sensationalist by popular audiences. This is because the ability of other animals to raise human children calls many long-standing assumptions about human uniqueness and superiority into question. However, our knowledge of the capabilities of other animals is increasing rapidly. As a result we are forced to recognise that they too are capable of many behaviours and actions previously thought to be exclusively human. Also increasing are documented cases of animals from a variety of different species showing empathy towards vulnerable others. Or rescuing them from a range of different circumstances. And so the stories of feral children become more plausible.</p><img src="https://counter.theconversation.com/content/59338/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Samantha Hurn 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>Our interest in feral children has a long history in truth and legend.Samantha Hurn, Lecturer in Anthropology and Programme Director for MA and PhD Anthrozoology, University of ExeterLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/355552015-02-02T19:03:38Z2015-02-02T19:03:38ZFeral feast: cats kill hundreds of Australian animals<figure><img src="https://images.theconversation.com/files/68432/original/image-20150108-1971-ce82gh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Feral cats eat tens of millions of native animals in Australia every night.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/anothereye/7736422878">Another Eye</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span></figcaption></figure><p>Feral cats are estimated to eat tens of millions of native animals <a href="https://theconversation.com/to-eradicate-feral-cats-we-need-to-know-how-many-are-out-there-33014">each night</a> in Australia. But what kinds of wildlife are they eating? In <a href="http://onlinelibrary.wiley.com/doi/10.1111/jbi.12469/abstract">research published today</a> in the Journal of Biogeography, my colleagues and I show that cats kill hundreds of different kinds of animals, including at least 16 species considered globally threatened. </p>
<p>Feral cats are a serious threat to wildlife globally, contributing to the extinction of numerous birds, mammals and reptiles <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2486.2011.02464.x/abstract">worldwide</a>. In Australia, cats have been implicated in the extinction of at least 20 mammal species and sub-species, including the lesser bilby and desert bandicoot. </p>
<p>Cats are widespread across the country, so it’s likely that their diet varies according to the local environment and fauna community – which might be affected by many factors, such as the amount of rainfall that an area receives or the native plant life.</p>
<p>Knowing what cats eat can help us decide how best to manage them. </p>
<h2>Feline feast</h2>
<p>What we found supports earlier research – the feral cat is an opportunistic predator - a generalist carnivore that eats a wide range of wildlife across Australia.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/68640/original/image-20150112-23792-n8vypq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/68640/original/image-20150112-23792-n8vypq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/68640/original/image-20150112-23792-n8vypq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=656&fit=crop&dpr=1 600w, https://images.theconversation.com/files/68640/original/image-20150112-23792-n8vypq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=656&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/68640/original/image-20150112-23792-n8vypq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=656&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/68640/original/image-20150112-23792-n8vypq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=824&fit=crop&dpr=1 754w, https://images.theconversation.com/files/68640/original/image-20150112-23792-n8vypq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=824&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/68640/original/image-20150112-23792-n8vypq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=824&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A feral cat degustation.</span>
<span class="attribution"><span class="source">Tim Doherty</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Feral cats help themselves to a phenomenal number of species in Australia – 400 different vertebrates. This includes 123 bird species, 157 reptiles, 58 marsupials, 27 rodents, 21 frogs and nine exotic medium- and large-sized mammals. This is more than double the 179 species of animals that cats have been <a href="http://link.springer.com/article/10.1007/s10530-010-9851-3">recorded</a> eating on other islands worldwide. </p>
<p>However, this list only includes those species that have been recorded in diet studies, so it’s likely that there are many other species of native animals that cats kill and eat, that we just don’t know about yet.</p>
<p>Feral cats also eat many threatened species in Australia, and have been <a href="http://www.environment.gov.au/system/files/resources/91832626-98e3-420a-b145-3a3199912379/files/tap-cat-background.pdf">implicated in the decline</a> of many species including the bilby, numbat, and <a href="http://tinyurl.com/q8f8vlp">western ground parrot</a>.</p>
<p>We found that cats kill at least 16 globally threatened species and 12 others classed as near-threatened. This include mammals like the critically endangered mountain pygmy-possum and the brush-tailed bettong (<a href="http://www.publish.csiro.au/paper/ZO14024.htm">woylie</a>); the endangered northern quoll; as well as the critically endangered Christmas Island whiptail-skink and the vulnerable malleefowl. </p>
<h2>Desert desserts</h2>
<p>What feral cats eat varies depending on where they are.</p>
<p>In our study, cats ate rodents most often in Australia’s tropical north. They ate medium-sized mammals, such as possums and bandicoots, most frequently in the south-east of the country. Still, cats ate rodents three times more often than other small, carnivorous mammals known as dasyurids (like dunnarts for example). </p>
<p>Cats also ate many mammals from a group that has suffered severe declines and extinctions over the past 200 years. These are known as “critical weight range” mammals, and weigh between 0.35 and 5.5 kilograms. Unfortunately, these mammals make suitable sized prey for many predatory species such as the feral cat and the introduced red fox. </p>
<p>What cats eat also depends on the amount of rainfall an area receives. Cats fed on reptiles most frequently in the central deserts, where rainfall is lowest. These deserts are also the most reptile-rich part of Australia (and the world).</p>
<p>Cats commonly feed on another widespread pest species: rabbits. Where cats ate fewer rabbits, the frequency of small mammals (rodents and dasyurids) in their diet increased. In Australia’s tropical north where rabbits are mostly absent, cats ate the highest frequency of rodents and dasyurids of anywhere in the country.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/68424/original/image-20150108-2005-1ey70kd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/68424/original/image-20150108-2005-1ey70kd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=510&fit=crop&dpr=1 600w, https://images.theconversation.com/files/68424/original/image-20150108-2005-1ey70kd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=510&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/68424/original/image-20150108-2005-1ey70kd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=510&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/68424/original/image-20150108-2005-1ey70kd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=641&fit=crop&dpr=1 754w, https://images.theconversation.com/files/68424/original/image-20150108-2005-1ey70kd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=641&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/68424/original/image-20150108-2005-1ey70kd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=641&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Rabbits are a major food source for feral cats.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/e3000/5454005947">Eddy Van 3000</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>This has important implications for how we manage pest animals. If rabbits are culled from an area, but cats aren’t controlled at the same time, then cats might switch prey and eat more small native mammals.</p>
<p>Past experience tells us how these programs can go awry. For example, when feral cats were eradicated from Macquarie Island in 2000, rabbit numbers exploded because the cats had kept the rabbits in check. Rabbits caused severe damage to the island’s native vegetation before being <a href="http://www.parks.tas.gov.au/?base=12997#History">eradicated themselves in 2014</a>. This suggests that a multi-species approach should be adopted for pest animal control.</p>
<h2>Cat control</h2>
<p>Large-scale control of feral cats is very difficult, particularly on the mainland, although some programs have <a href="http://www.environment.gov.au/system/files/resources/91832626-98e3-420a-b145-3a3199912379/files/tap-cat-background.pdf">been successful on islands</a>. The use of poison baits can reduce cat density, but even low levels of cat predation can exterminate threatened mammal <a href="http://www.sciencedirect.com/science/article/pii/S0006320711003119">populations</a>, such as when cats killed at least seven bilbies reintroduced outside the Arid Recovery reserve in South Australia.</p>
<p>Predator-free islands and fenced reserves on the mainland are the most effective short-term protection for our threatened mammals. However, fences that exclude predators are very expensive to build, and they require constant monitoring, maintenance and funding.</p>
<p>Non-lethal methods have traditionally been overlooked in the fight against invasive predators, such as the feral cat. However, <a href="https://theconversation.com/predators-get-the-advantage-when-bushfires-destroy-vegetation-32821">new research</a> suggests that smart fire and grazing management can help preserve the natural shelters that provide native animals with refuge from predators.</p>
<p>Reducing the impact of feral cats on our native animals is a challenging endeavour, but it is essential in the fight to conserve our unique fauna.</p><img src="https://counter.theconversation.com/content/35555/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tim Doherty receives funding from Earthwatch Institute Australia, the Holsworth Wildife Research Endowment and Edith Cowan University.</span></em></p>Feral cats are estimated to eat tens of millions of native animals each night in Australia. But what kinds of wildlife are they eating? In research published today in the Journal of Biogeography, my colleagues…Tim Doherty, PhD Candidate, Edith Cowan UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/199142013-11-13T19:42:16Z2013-11-13T19:42:16ZHow desexing cats saves lives<figure><img src="https://images.theconversation.com/files/35009/original/qjpq5hsm-1384233118.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A feral cat by the roadside.</span> <span class="attribution"><span class="source">EPA/Nic Bothma</span></span></figcaption></figure><p>Thousands of unowned cats wander Australian streets every night. Some are feral, existing in self-sustaining populations not reliant on people, while others are semi-feral and are either fed by people or scavenge discarded food. </p>
<p>Those cats hunt native fauna and harbour disease and parasites that can be passed on to humans, pets and wildlife. </p>
<p>Yet depending on where you live in Australia, the rules on desexing and registering your cat can vary wildly. The result? Greater risks to human health, and tens of thousands of kittens and cats needlessly killed in animal shelters every year.</p>
<h2>Pets and parasites</h2>
<p>Many cats carry the parasite <a href="http://joomla.wildlife.org/documents/cats_toxo.pdf"><em>Toxoplasma gondii</em></a>, which can be passed to humans through litter trays, soil and undercooked meat. </p>
<p>The risk is greatest for pregnant woman and people with compromised immune systems. An unborn foetus with Toxoplasmosis can suffer permanent neuorological damage or even miscarriage or stillbirth. </p>
<p><a href="http://www.ncbi.nlm.nih.gov/pubmed/19744306">Research has shown</a> how we can reduce those risks to humans and unborn babies, including by educating cat owners about the importance of collecting cat faeces in litter boxes, desexing pet cats to reduce overpopulation and reducing the numbers of feral cats.</p>
<p>So there are clear benefits to human health of managing our cat population. But desexing is the kinder thing to do for cats too - not least because it avoids so many cats and kittens being put down.</p>
<h2>Life on the streets</h2>
<p>Many feral and semi-feral cats experience poor health and animal welfare outcomes because they are not owned or cared for like a pet cat. </p>
<p>Local councils and animal shelters have to <a href="http://www.ccac.net.au/files/Cat%20Admission%20to%20Melbourne%20Shelters%20Final%20Report_0.pdf">euthanase tens of thousands of cats</a> each year because they are in poor health, are behaviourally unsuited to adoption or homes cannot be found for them. </p>
<p>More than 30,000 impounded cats were put down <a href="http://www.dlg.nsw.gov.au/dlg/dlghome/documents/Information/Companion%20Animals%20Taskforce%20-%20Report%20to%20Ministers.pdf">in NSW alone during 2010/11</a>.</p>
<h2>Killing kittens</h2>
<p>A high shelter admission rate of kittens by owners indicates that unwanted litters by pet cats are a significant contributor to the problem. </p>
<p>In Queensland, 6950 kittens were surrendered by owners to <a href="http://onlinelibrary.wiley.com/doi/10.1111/avj.12013/full">animal shelters</a>, with kittens making up one-fifth of cats in the state’s shelters. And 61% of all kittens had to be euthanased because homes could not be found for them.</p>
<p>But we have no way to track how many unwanted kittens are also abandoned to join feral and semi-feral populations, on top of the unowned kittens born to feral or semi-feral cats mating with pet cats.</p>
<h2>Desexing prevents unwanted litters</h2>
<p>Mandatory desexing of pet cats from an early age would help prevent pet cats having unwanted litters, and the associated problems of surrender to animal shelters, abandonment or interbreeding with feral and semi-feral populations. </p>
<p>While desexing rates for pet cats in Australia are already above 90%, which is high by international standards, many cats are not desexed until later in life so they have opportunities to breed. </p>
<p>Cats may breed from four months old, so desexing of young kittens is needed to prevent breeding altogether. Given veterinary evidence that anaesthetic risks in young cats can be controlled and that adverse outcomes are no higher than for older cats, increasing numbers of cat rescue organisations are endorsing desexing of pre-pubescent kittens.</p>
<h2>Australian laws on pet cats</h2>
<p>Since 1 November this year, if you’re a West Australian cat owner, <a href="http://www.dlg.wa.gov.au/Content/Legislation/ResponsibleCatOwnership.aspx">it’s become mandatory</a> to desex, microchip and register any cats you have with a local council by the time the cat is six months old. </p>
<p>The only exceptions to mandatory desexing are cats owned by licensed breeders or cats certified by a veterinarian as having poor health risks for surgery. Pet cats must also wear an ID tag. </p>
<p>If the number of owner-admitted unwanted cats can be reduced through mandatory desexing, rehoming of other cats from shelters will increase, which should result in a lower euthanasia rate. The hidden problem of abandonment of unwanted kittens should also be reduced.</p>
<p>While desexing may seem like a logical step in reducing cat populations, WA and the <a href="http://www.tams.act.gov.au/city-services/pets/Cats_in_the_ACT">Australian Capital Territory</a> are the only parts of Australia where the practice is mandatory. </p>
<p>Registration and desexing are not mandatory in South Australia, Tasmania, the Northern Territory or Queensland, although it may be a requirement of some local councils. </p>
<p>In contrast to what has happened in WA, the <a href="http://www.brisbanetimes.com.au/queensland/brisbane-scratches-cat-registration-20131005-2v0zm.html">Queensland government has recently repealed</a> state legislation for mandatory cat registration, arguing it’s a win for cat owners and for reducing <a href="http://www.daff.qld.gov.au/services/news-and-updates/animals/news/changes-to-mandatory-cat-registration">“red tape”</a>.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/34921/original/hmsfwcb9-1384171509.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/34921/original/hmsfwcb9-1384171509.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/34921/original/hmsfwcb9-1384171509.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/34921/original/hmsfwcb9-1384171509.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/34921/original/hmsfwcb9-1384171509.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/34921/original/hmsfwcb9-1384171509.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/34921/original/hmsfwcb9-1384171509.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 summary of the different state and territory legal requirements for cat ownership in Australia. Source: WA Department of Local Government and Communities, ACT Territory and Municipal Services, NSW Division of Local Government, VIC Department of Environment and Primary Industries, NT Department of Primary Industry and Fisheries, QLD Department of Agriculture, Fisheries and Forestry, SA Dog and Cat Management Board, TAS Department of Primary Industries, Parks, Water and Environment.</span>
</figcaption>
</figure>
<p>But in our opinion, Queensland is taking a backward step by joining with South Australia, Tasmania and the Northern Territory in adopting such a hands-off approach.</p>
<p>In doing so, we are likely to see more unwanted kittens and cats born that will end up being put down in our shelters. And it risks increasing the problems of animal welfare, wildlife management and public health problems associated with large populations of semi-feral and feral cats. </p>
<p>Addressing these issues requires strong leadership from state and territory governments, commitment by local councils to enforce regulations, and responsible cat ownership in the community.</p>
<p>The health risks to humans, as well as the huge number of kittens being born only to be killed, are too high for this issue not to be taken more seriously.</p><img src="https://counter.theconversation.com/content/19914/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tim Doherty receives funding from Earthwatch Institute Australia and the Holsworth Wildlife Research Endowment.</span></em></p><p class="fine-print"><em><span>Mike Calver is affiliated with the Cat Haven shelter in Western Australia.</span></em></p>Thousands of unowned cats wander Australian streets every night. Some are feral, existing in self-sustaining populations not reliant on people, while others are semi-feral and are either fed by people…Tim Doherty, PhD Candidate, Edith Cowan UniversityMike Calver, Associate Professor in Biological Sciences, Murdoch UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/182622013-09-25T05:45:45Z2013-09-25T05:45:45ZIntroducing species to change ecosystems is a balancing act<figure><img src="https://images.theconversation.com/files/31795/original/wpmynncc-1379946108.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Bird feed now. The whole bird later.</span> <span class="attribution"><span class="source">vermininc</span></span></figcaption></figure><p>Species hold ecosystems in a delicate balance. From time to time humans introduce non-native species to an ecosystem, because they may be needed for domestic work, as pets, for carrying loads or even for killing previously introduced species. In each case, their introduction changes how the ecosystem works. And sometimes things go wrong, leading to the decline of many native species.</p>
<p>Despite studying introduced species for more than 200 years, we understand only a little about them. The reason is that studying their complex interactions with other species can be difficult. The ideal places to carry out such studies are islands. Their physical boundaries makes it easy to keep track of a limited number of species and their interactions.</p>
<p>But even if an ecosystem is studied, it is usually difficult to apply those lessons to a different ecosystem because of the quirks of each. Emily Hanna and Marcel Cardillo of the Australian National University thought perhaps a larger scale study done on many islands might give the best insight into introduced species. That is why they decided to study 934 mammal population in 323 Australian islands. There are many islands with and without different introduced predators, which makes Hanna and Cardillo’s analysis strong. </p>
<p>They report their results in a recent study published in the journal <a href="http://onlinelibrary.wiley.com/doi/10.1111/geb.12103/abstract">Global Ecology & Biogeography</a>. Broadly, they asked two questions - First, how do introduced mammal predators affect one another and native species? Second, do geographic attributes such as terrain or distances affect extinction rates of mammals?</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/31723/original/vnxrgjwx-1379666595.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/31723/original/vnxrgjwx-1379666595.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=139&fit=crop&dpr=1 600w, https://images.theconversation.com/files/31723/original/vnxrgjwx-1379666595.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=139&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/31723/original/vnxrgjwx-1379666595.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=139&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/31723/original/vnxrgjwx-1379666595.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=175&fit=crop&dpr=1 754w, https://images.theconversation.com/files/31723/original/vnxrgjwx-1379666595.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=175&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/31723/original/vnxrgjwx-1379666595.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=175&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Black rat, feral cat, fox and dingo.</span>
<span class="attribution"><span class="source">H. Zell, Batty, Jonn Leffmann and PartnerHunt.com, respectively</span></span>
</figcaption>
</figure>
<p>These islands off Australia are particularly interesting for such study because they suffer from a high rate mammal extinctions (more than 25%). The blame is being put on introduced predators. There are at least eight species that were previously widespread on the Australian mainland but are now confined to islands. </p>
<p>Updating older databases revealed that these islands had 934 mammal populations of 107 species from 323 islands. They then identified the most common introduced predators and categorised them into three size groups: small (black rat, <em>Rattus rattus</em>), medium (domestic cat, <em>Felis catus</em>, and red fox, <em>Vulpes vulpes</em>) and large (dingo, <em>Canis lupus dingo</em>, feral domestic dog, <em>Canis lupus familiaris</em>, and their hybrids). </p>
<p>Hanna and Cardillo’s first conclusion agreed with previous studies - introduced predators cause extinctions of native mammals on islands. But things were not as simple as that. Their results provided support for the mesopredators suppression hypothesis, which says that top predators, such as cats, foxes, dingos or feral dogs can reduce extinction of prey species by suppressing the influence of mesopredators (smaller predators such as black rats). But they also found that extinction was higher on islands where black rats were present without introduced apex predators (cats, foxes, dingo and feral dogs).</p>
<p>Next, they found that body size was a predictor of extinction risk. Larger mammals were more prone to extinction on islands compared to smaller bodied mammals (Large defined as more than 2.7 kg). For larger mammals island biogeography was found to be a key predictor of extinction risk - the further the island from the mainland, the more prone those mammals were to extinction. By contrast, for smaller mammals the presence of invasive species was a key predictor of extinction risk.</p>
<p>While the black rat was the chief culprit in this study, Hanna and Cardillo’s work may also extend to other systems in which the effects of smaller invasive predators may similarly be mitigated by larger predators. For a conservationist, Hanna explained the implications of this study, “Eradication of smaller and larger introduced species needs to be balanced. If only the apex predator is eradicated, the mesopredator population could rapidly increase in size, possibly sending native mammal populations extinct.”</p><img src="https://counter.theconversation.com/content/18262/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>William Feeney receives funding from The Australian National University and Australian Geographic. He is affiliated with The Australian National University.</span></em></p>Species hold ecosystems in a delicate balance. From time to time humans introduce non-native species to an ecosystem, because they may be needed for domestic work, as pets, for carrying loads or even for…William Feeney, Australian National UniversityLicensed as Creative Commons – attribution, no derivatives.