Pomarine Jaeger (Stercorarius pomarinus)
White-winged Tern (Chlidonias leucopterus)
Pale and dark morphs. Often difficult to distinguish from Arctic Skua. Adults with broad, spoon-shaped streamers. These are moulted twice a year, so adults lacking these are not uncommon. The dark cap reaches around the bill base and down to the chin. Breast band in pale morph is generally broader and more pronounced than in Arctic Skua, but in some males it is lacking altogether. Leaves an overall more robust and powerful impression than Arctic. Wings are broader than the distance from trailing wing-edge to tip of tail (streamers excluded), while the hand seems shorter. The light patches at the base of the primaries are more obvious, and many young birds shows a characteristic double patch, formed by additional white base of greater primary coverts (like Lesser Spotted Eagle). Rump and vent of juveniles usually boldly barred, in contrast to unbarred back and belly (visible even in dark morph). Streamers never pointed (in any plumage). Flight pattern straighter, and more determined than in Arctic Skua.
Sound:Short "kea" or "ke", and various mewing calls, usually deeper pitched than Arctic Skua. Also a characteristic, laughing and vibrating "kayayayayaya", heard mostly on breeding ground.
Alarm/flight 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-photo:loarie, Licence,Link.
CC-photo:jerryoldenettel, Licence,Link.
Sounds:CC. http://www.xeno-canto.org .Recorded by Andrew Spencer.
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.