Caspian Tern: Large, stocky tern with pale gray upperparts, white underparts. Cap is black and may appear weakly crested; large bill is coral-red. Undersides of primaries are gray. Tail is white, relatively short, and slightly forked; legs are black. Hovers above water before diving.
Range and Habitat
Caspian Tern: Breeds in scattered colonies from Mackenzie, Great Lakes, and Newfoundland south to the Gulf coast and Baja California. Spends winters north to California and North Carolina. Also breeds in Eurasia, Africa, and Australia. Preferred habitats include sandy or pebbly shores of lakes and large rivers and along coasts.
The Caspian Tern aggressively defends its breeding colony. It will pursue, attack, and chase potential predatory birds, and can cause bloody wounds on the heads of people who invade the colony. The entire colony will take flight, however, when a Bald Eagle flies overhead, exposing the chicks to predation from gulls.
The largest breeding colony in North America is off the coast of Oregon. Increasing numbers of terns at this site have caused problems with young salmon releases, some of them endangered species. Efforts are being made to move the colony to other areas, away from the fish stocking programs.
Young Caspian Terns appear to have a difficult time learning to catch fish efficiently. They stay with their parents for long periods of time, and are fed by them even on the wintering grounds. Many young terns do not return to the nesting grounds for several years, remaining instead on the wintering areas.
A group of terns are collectively known as a "ternery" or a "U" of terns.