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:

Differs from Common and Arctic Tern by; noticably shorter wings, longer streamers, much paler grey upperparts, pure white underparts (faint rosy wash not very conspicuous), black bill (red base in breeding birds), dark outer primaries and no dark edge to inner primaries. Amount of red in bill increases as breeding season progresses, but also varies geographically. Wingbeats shallower and much quicker than in Common and Arctic Tern. Fishes with characteristic diagonal dives. Despite the long streamers, the birds appear short-tailed in flight, but head and bill are long and slender. The pale plumage, dark bill and giss recalls a small Sandwich Tern. Adult winter plumage with all dark bill and white forehead. Juveniles resembles juvenile Sandwich Terns, with more complete dark cap than Arctic and Common, and much more contrasting markings on back (especially to wings).

Sound:

Extremely harsh calls. Like mix of Caspian and Arctic Tern. Very hard and raspy "kreeeet", harder and higher pitched than Caspian Tern, but equally harsh. Other calls include more Arctic/Common tern-like short "kek", and similar.

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:USFWS/Southeast, Licence,Link.

CC-photo:Werner Witte, Licence,Link.

CC-photo:Anita363, Licence,Link.

CC-photo:Mike Prince, Licence,Link.