Snowy Owl (Bubo scandiacus)
White-winged Tern (Chlidonias leucopterus)
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
Image search Flickr NB! May give other species
CCCC-sound:Niels Krabbe, Licence,Link.
Breeding adult easily identified by white tail/rump combined with jet black under wing coverts and silvery upper wing. Immature with brownish back contrasting with pale, silvery upper wings and pale rump. Broad white collar, and lacks dark breast patch of immature Black Tern. Adult winter most liable to confusion with other terns, but upperparts much paler than Black Tern. Contrasting dark outer primaries and secondaries to rest of wing. Often retains some black under coverts even in winter which is diagnostic if seen. Slightly more compact than Black Tern and often recalls Little gull in shape. Bill noticeably shorter and thinner than in Whiskered Tern.
Sound:Mostly silent away from breeding ground. Most diagnostic call a dry, rolling "krrrrrr-ta-ta" where the rolling is followed by one or two accentuated syllables, or just simply "krrrrrr". Used in excitement.
Call:
Distribution:
Xeno-canto: map
Ecology:Birdlife ecology
Links:
Observation.org Latest observations
Image search Flickr NB! May give other species
CCCC-sound:Marco Dragonetti, Licence,Link.