The Black Tern, Chlidonias niger, is a small tern.
Adult birds have short dark legs and a short black bill. They have a dark grey back, with black head, neck and belly with a light grey tail. In non-breeding plumage, most of the black, apart from the cap, is replaced by grey.
The North American race, C. n. surinamensis, is distinguishable from the European form in all plumages, and is considered by some to be a separate species.
Their breeding habitat is freshwater marshes across most of Canada, the northern United States and much of Europe and western Asia. They usually nest either on floating material in a marsh or on the ground very close to water, laying 2-4 eggs.
North American Black terns migrate to the coasts of northern South America, some to the open ocean. Old World birds winter in Africa.
Unlike the "white" Sterna terns, these birds do not dive for fish, but forage on the wing picking up items at or near the water's surface or catching insects in flight. They mainly eat insects and fish.
The North American population has declined in recent times due to loss of habitat.
