Appearance:

Adults in summer at close range unmistakable. Bill in juveniles almost black, and much less deep than in adults. Adults in winter plumage also show much darker bill and cheeks than in summer. At a distance head gives an all dark impression, with characteristic dark "shadow " in front of the eye. Head and bill less elongated than in other auks. Wings rounded with dark undersides. "Thighs" dark. Flight fluttering and energic, with shifting weight and angle.

Sound:

Deep, but not so coarse as Razorbill. Smoother and more gliding changes in pitch, like a "slow-motion" laugh or distant chainsaw; "aaaahrrr, aahr, ahr arh".

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

CC-photo:zanzamos, Licence,Link.

Sounds:Recorded by Hans Petter Kristoffersen,http://www.xeno-canto.org ,CC license

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.