Appearance:

Very large tern, with deep, dagger-like, blood-red bill with dark tip. Large, black cap reaching well below the eyes. Grey upperparts and white underparts. Rather short tail. Outer primaries distinctly darker than the rest of upperwing, and outer underwing almost black. Unmistakable from the size alone, and leaves a gull-like impression, lacking the elegance of smaller terns. Immatures with paler bill and white forehead (as in adult winter), and markedly speckled back. Hovers and dives. Often rests on the surface, feeding like a gull.

Sound:

Easily recognized by its very harsh calls. Sometimes likened to the sound of a plate of steel being dragged across a concrete floor. Similar in harshness to Grey Heron, but more drawn, with an accented middle; "Kraaeeet", or with a double syllable start "ka-ha-kraaaeet". Immature birds begs with a penetrating, sharp whistle.

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

CC

CC-photo:lgooch, Licence,Link.

CC-photo:Muchaxo, Licence,Link.

CC-photo:ajmatthehiddenhouse, Licence,Link.

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.