The male Bufflehead performs his extravagant courtship display often. He swims toward the female, bobbing his head up and down at a speed that makes you fear for his neck. He takes off and flies over her with head held low. Then he lifts his head, raises his bushy crest, and skis back on…

Related to shearwaters and petrels, the Northern Fulmar will eat just about anything it finds on the surface of the ocean, from fish and squids to dead whales. Fulmars are polymorphic, that is to say they come in more than one color. This difference is independent of sex and age. The…

Despite its name, the Northern Waterthrush is really not a thrush: it's a warbler. But unlike most warblers, waterthrushes feed on the ground. They winter in the tropics, where they frequent the edges of ponds and mangrove swamps. Where might you find a Northern Waterthrush? Find out at…

Ornithologists think a glitch in a gene that controls migration in Tropical Kingbirds causes them to fly in exactly the wrong direction. From their Arizona breeding grounds, they head northwest in fall, rather than southeast to their usual wintering haunts in Mexico. Learn more at Cornell…

Not only do Cackling Geese sound different, but they also look different from Canada Geese, and their DNA is different. The Cackling Goose was defined in 2004 as a species separate from the Canada Goose.