Appearance:

Large and bulkily built diver with heavy bill, square head profile and steep forehead. Usually holds bill pointed straight, not uptilted like White-billed Diver. Summer: White underparts and chequered black back. Black bill and head. Neck with white band. Winter; white underparts and dark back. Neck with incomplete black band, creating contrasting, jagged edge. Heavy, goose-like flight.

Sound:

Song: Like a slow Black-throated Diver. Pitch slowly rising with a register break, progressing into a cyclic, two to four syllable, motif. Also various vibrating eerie descending calls. Often used as sound effect in horror movies.

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

CC

CC-photo:jackanapes, Licence,Link.

CC-photo:jerryoldenettel, Licence,Link.

Sounds:Recorded by Patrick Åberg,http://www.xeno-canto.org ,CC license

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.