You've heard pregnant women talk about nesting, whether that's painting the nursery, or cleaning the house from top to bottom before their baby arrives. But new research turns 'nesting' on its head.
A male Olive-backed Euphonia (Euphonia gouldi), photographed in Costa Rica.
Andy Morffew
Birds spend a lot of time and energy singing, but they don't do it the same way in every season of the year. And some can't sing at all. What's the purpose of birdsong?
Nests are not for sleep. They are for babies.
Flickr/Anna Hesser