Tundra Swan (Cygnus columbianus)
White-winged Tern (Chlidonias leucopterus)
Easily confused with Whooper Swan, but yellow on bill restricted to a rounded patch. May sometimes extend towards the bill-tip, but never beyond nostrils. Angle of mouth bold black. Gives a more compact impression than Whooper, due to shorter neck. Head shape noticeably more rounded, and seemingly larger. Juveniles paler grey than Whooper, with the same bill pattern as in adults, but in faint, pale yellow and pink. Flight easy and goose-like.
Sound:More vocal than other swans. Both higher pitched and deeper sounds. Birds on the water often gives crooning, crane-like notes with less defined pitch. Tone is less full-bodied in these calls. Flight call a deep, yelping, soft barking sound. Each call short, with a "helpless" quality.
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
CCBreeding 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.