Feathers and Radiation

Turns out that colorful feathers (due to carotenoid-based pigments) use up antioxidants, which makes the birds vulnerable to ionising radiation. (Antioxidants would help protect the birds from free radicals.) Colorful birds around the Chernobyl nuclear plant have declined, as have other birds with activities that reduce their natural antioxidants (birds that lay large eggs and birds that migrate longer distances). From the Eurekalert:

"Among the brightly coloured species most affected were orioles, blackbirds and blue tits, while drab species like tree pipits, coal tits and chaffinches were much less affected. Long distance migrants or dispersers that were most affected included quails, orioles, hoopoes, blackbirds and robins, while non-migrant or short-dispersing species like great tits, coal tits and song thrushes were much less affected."