One of the three species of "marsh terns", it is similar to Black Tern (Chlidonias niger) but shows more contrast with darker back, brilliant white rump, white leading edges of wings and black underwing coverts. Adult in summer plumage easily recognised by the jet black body and underwing coverts. In winter plumage lacks black neck patch of Black Tern.

Breeds in freshwater marshes, wetlands and swamps.

Mostly May to September.

Breeds on south-eastern Europe. Seen on passage along coasts.

Annual vagrant

Rare vagrant from south-eastern Europe. Less than twenty records from our area.