Gull-billed Tern

The gull-billed tern is a fairly large, powerful tern, 33–42 centimetres long with a wingspan of 76–91 centimetres and a mass of 150–292 grams. It resembles a Sandwich tern, but the short, thick, gull-like bill, broad wings, long legs and robust body are distinctive. The summer adult has grey upperparts, white underparts, a black cap, a strong black bill and black legs. In winter the cap is lost, leaving a dark patch through the eye. The call is a characteristic ker-wik. (Wikipedia, general species account)

It is widely distributed and breeds in scattered localities in the warmer parts of the world: southern Europe, temperate and eastern Asia, northwest Africa, both coasts of North America and eastern South America. It has a number of geographical races that differ mainly in size and minor plumage details. All forms disperse after breeding, and the northern breeders are the most migratory, wintering south to Africa, the Caribbean, northern South America, southern Asia and New Zealand. (Wikipedia, general species account)