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.

Appearance:

Large gull with deep chest, light grey back and heavy yellow bill with red spot (adult). Pinkish legs and black tipped primaries with white windows. Winter plumage with streaked head and neck. Develops grey mantle in 2.nd winter. Young birds may be difficult to distinguish from juvenile Greater- or Lesser Black-backed Gulls, and the species shows notable variation in both plumage and size. Juveniles generally shows darker head and less contrasting markings than Greater Black-back, and pale inner primaries (window), as opposed to the all black hand of young Lesser Black-backs.

Sound:

Quite vocal. A long and strong "ay-kay-kay-kay-kay" with fading strength commonly heard. A deep "ga-ga-ga" heard from anxious birds. All calls much deeper pitched than Common Gull. Difficult to distinguish from Lesser Black-backed Gull, but tone is less nasal.

Contact call and song:

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:Jens Kirkeby, Licence,Link.