Marsh tern
A member of the genus Chlidonias, part of the family Sternidae. In the British Isles the only regularly occurring example is the Black Tern C. niger. Marsh terns are predominantly freshwater birds, while the other members of the family (mostly placed in the genus Sterna) are predominantly marine in the British Isles and so are referred to as 'sea terns' (for example the Common Tern S. hirundo).From Peter Weaver's Birdwatcher's Dictionary
Copyright © 1981 by Peter Weaver