Appearance:

Unmistakable in breeding plumage, but otherwise easily confused with other marsh terns. Breeding plumage with black head and belly, but pale underwing and grey rump. When in immature and winter plumage it differs from Common and Arctic tern by smaller size and short, moderately forked tail, and from other marsh terns by slimmer body and wings (compared to White-winged tern), and relatively long, thin bill. Both immature and adult winter show dark front edge of wing, and characteristic dark shoulder patch at wing base. Back is dark in immature birds. Grey rump in all plumages. Flight usually different from Sterna-terns, with erratic dives for no apparent reason, and "aimless" change of direction. Note that when foraging over saltwater, flight becomes more Sterna-like.

Sound:

Moderately vocal. Flight call a more or less clear "kleck, or a disyllabic "klee-ake" with accented first syllable. Sometimes slightly rolling "klirr-eke", but never as much as in White-winged Tern. Also a slightly harsher "kreek", but not as raspy as in Whiskered Tern.

Flight call:

Distribution:

Wikipedia: map (se also Xeno-canto below)

Ecology:

Birdlife ecology

Links:

Observation.org Latest observations

Video IBC

Image search Flickr NB! May give other species

Sound search at Xeno-canto

Featherbase

CC

CC-sound:Ad Postma, Licence,Link.

Appearance:

At a distance quite similar to Guillemot. Bill deep, rectangular and with white markings. Flanks unstreaked and armpits white. Tail longer than in Guillemot, with legs not protruding behind tail in flight. Tail often held clear of the surface when swimming. Cheeks white in winter, with broad, short and black eye stripe. Neck collar short and wide. Upperparts blacker, and underparts whiter than Guillemot. Heavy neck, head and bill, in combination with the long tail, gives it a front heavy, and different profile from Guillemot, whether perched, swimming or flying. Top of head in line with tip of uptilted bill when swimming.

Sound:

Very coarse and deep voice. Grunting or snore-like, with little phrasing. Mostly heard at breeding ground, but also sometimes at sea.

Contact call:

Distribution:

Wikipedia: map (se also Xeno-canto below)

Ecology:

Birdlife ecology

Links:

Observation.org Latest observations

Video IBC

Image search Flickr NB! May give other species

Sound search at Xeno-canto

Featherbase

CC

Sounds:Recorded by Simon Elliott,http://www.xeno-canto.org ,CC license