Why some birds decorate their nests with snake skin: The reason is brilliant

If you've ever seen a bird's nest lined with what looks like a snake's shed skin, you're not imagining things. A study published in February 2025 in The American Naturalist found that cavity-nesting birds use snake sheds to deter would-be predators from eating their eggs and nestlings. The behavior's been documented for centuries. Birdwatchers have been noting it since at least the 1800s. But until recently, it was treated more like a curiosity than something worth understanding. Vanya Rohwer, the study's lead author and curator of birds and mammals at Cornell University, realized there must be some ecological motivation behind the behavior. So he and his team decided to find out why birds were actually investing all that time and effort into finding something as strange as a shed snakeskin.