Caspian Tern(redirected from Hydroprogne)
(Hydroprogne caspia), a bird of the family Laridae of the order Charadriiformes. The body is about 50 cm long and weighs about 650 g. The bird is gray above and white below, with a black head cap and black legs. The Caspian tern is distributed sporadically in Europe (except the north), Western and Southeast Asia, Australia, New Zealand, Africa, and North America. In the USSR it is found along the Baltic, Black, Azov, Caspian, and Aral Seas, as well as along lakes of Kazakhstan, Transbaikalia, and the southern Primor’e. The Caspian tern is a migratory bird. It nests in colonies on shoals and islands. A clutch contains two or three eggs, which are incubated by both parents for 22 or 23 days. The Caspian tern feeds on small fish, invertebrates, and, sometimes, the young of other birds.