The white-winged tern, or white-winged black tern (Chlidonias leucopterus or Chlidonias leucoptera), is a species of tern in the family Laridae. It is a small species generally found in or near bodies of fresh water across much of the world, including Europe, Africa, Asia, and Australia. The genus name is from Ancient Greek khelidonios, "swallow-like", from khelidon, "swallow".
The name 'white-winged tern' is the standard in most English-speaking countries; in the United Kingdom, this name is also the one used by the formal ornithological recording authorities, but the older alternative 'white-winged black tern' is still frequent in popular use. Their breeding habitat is freshwater marshes across from southeast Europe to central Asia. They usually nest either on floating vegetation in a marsh or on the ground very close to water, laying 2-4 eggs in a nest built of small reed stems and other vegetation. In winter, they migrate to Africa, southern Asia and Australia. It is a scarce vagrant in North America, mainly on the Atlantic coast, but a few records on the Pacific coast and inland in the Great Lakes area.
Like the other "marsh" terns (Chlidonias), and unlike the "white" (Sterna) terns, these birds do not dive for fish, but fly slowly over the water to surface-pick items and catch insects in flight. They mainly eat insects and small fish. In flight, the wing-beats are shallow and leisurely.
The white-winged tern is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) applies.
Source : Wikipedia