- Gavia arctica
Identification
ALSO KNOWN AS BLACK THROATED DIVER(Arctic Loon-North America) (Gavia arctica)
Identification: Medium-sized diver between Red-throated G. stellata and Great Northern G. immer in build. Adult breeding: upperparts blackish with rectangular white spots on back, most prominent on scapulars, and white below with black and white streaks on sides of upper breast. Head and neck grey, palest on hindneck, with black and white vertical stripes on sides of neck bordering black throat patch. Adult non-breeding: Dark grey-brown on head and upperparts clearly demarcated from white throat and underparts. Crown and nape are paler than back (unlike Great Northern) and flanks often show a white patch visible on a swimming bird. Intermediate build and bill held straight are best identifying features but very difficult to separate from Pacific Diver and may not be possible with non-breeding birds.
Length 68-73cm. Wingspan 120cm.
Range: Breeds in northern Scotland and the Hebrides, over much of Scandinvia and the Baltic States and across Russia to Sakhalin and Kamchatka, probably also northern China. Breeds in western Alaska but range unclear due to similarity of this species and recently split Pacific Diver G. pacifica. In winter ranges from the Baltic south to Biscay, the northern Adriatic and Black and Caspian Seas and a vagrant on the North African coast and the Canary Islands. In the far east winters off Japan, China and Taiwan. May also occur on Atlantic coast of North America.
Habitat: Breeds beside medium-large freshwater lakes, often with islands. On passage and in winter moves to coastal areas and occurs on estuaries, bays and sheltered seas.
Voice: Various wailing, croaking and quacking calls.
Breeding: Breeds early-May to September, begins mid-June in north of range. Nests beside water often on an island or spit, a shallow scrape or more rarely a substantial mound of vegetation built in shallow water. Eggs: 2 (1 in replacement clutch), olive-brown, sometimes more greenish with sparse black blotches (84 x 53mm). Incubated by both sexes for 28-29 days. Young tended by both sexes, feed themselves at 35 days and fly at about 60 days
Diet: Fish, also molluscs and crustaceans caught during 45-120 second dives.
Subspecies: Three subspecies recognised. Nominate race breeds across Europe and Russia with sushkini from western Siberia Central Asia and viridigularis (green-glossed throat patch) in north-eastern Siberia and western Alaska.
Photographed in West Sweden.
range
I believe in North America this species is normally found only in western Alaska and is casual elsewhere on the west coast and a very rare vagrant anywhere else on the continent, so not quite circumpolar. Glen Tepke
Originally posted by Glen Tepke
Bird Song
<flashmp3>Gavia arctica (song).mp3</flashmp3>
Listen in an external program
