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:

Largely unmistakable. Male almost pure white with black dots. Female and juveniles white with heavy black barring, and may seem grey at a distance. Juveniles more finely barred than adult females, giving them a greyer appearance, with white neck and face. Body barrel-shaped, head small and rounded. Wing-tips more pointed than in other owls. Flight action both buzzard and owl-like, with surprising agility. Note that several species of owls may seem completely white to the untrained eye when suddenly appearing in car headlights etc.

Sound:

Song consists of single utterances or series of "aooo", recalling Great Black-backed Gull, and is far carrying. Male warning call a deep and harsh "groat grat grat", with accented endings of each syllable. Female warning call higher pitched. Also various other high pitched calls.

Alarm 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:Niels Krabbe, Licence,Link.

CC-photo:ahisgett, Licence,Link.

CC-photo:Frank.Vassen, Licence,Link.