Hosts of brood parasites defend their nests against parasitism by aggression and subsequently, if parasitized, by rejection of the parasite egg or nestling. Cuckoos have evolved plumage mimicry with ...

Estonia and Austria, two European countries, have named this species their national bird. George Grinnell played a huge role in early conservation. After he became editor of Forest and Stream magazine ...

A new study led by the University of Colorado at Boulder has shown the testosterone of male North American barn swallows skyrocketed early in the breeding season when their breast colors were ...

If you are a male barn swallow in the United States or the Mediterranean with dark red breast feathers, you're apt to wow potential mates. But if you have long outer tail feathers in the United States ...