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| − | + | '''a.k.a. White-billed Diver; Yellow-billed Diver; ''' | |
;[[:Category:Gavia|Gavia]] adamsii | ;[[:Category:Gavia|Gavia]] adamsii | ||
[[Image:Yellow-billed_Loon.jpg|thumb|550px|right|Photo by Cancoot.<br/>Photo taken: Deep Bay, British Columbia, Canada.]] | [[Image:Yellow-billed_Loon.jpg|thumb|550px|right|Photo by Cancoot.<br/>Photo taken: Deep Bay, British Columbia, Canada.]] | ||
Revision as of 17:21, 27 June 2008
a.k.a. White-billed Diver; Yellow-billed Diver;
- Gavia adamsii
Identification
The largest diver
L. 75-91cm
W. 147cm
- Large pale bill
- Straight culmen with angled lower mandible gives a characteristic appearance enhanced by habit of holding bill at an upward angle as in much smaller Red-throated Diver.
Adult Breeding
Similar to Great Northern Diver
- White-chequered black back
- Glossy black head with white "necklaces"
- Differs in large, yellowish-white bill
Adult Non-breeding
Similar to Great Northern Diver
- Generally paler, particularly around the head and hindneck
- Face much whiter with dark eye isolated in white face
- Head and neck paler than back
- At all seasons bill is the best distinguishing feature
Distribution
Breeding
In North America breeds in northern Alaska and north-central Canada including many of the Arctic islands. In Eurasia breeds on the Arctic coast but range little-known. Has bred on Novaya Zemlya but main range lies to the east. May have further west in the Varanger area of Norway, on the Kola Peninsula and on Ostrov Kolguyev.
Non-breeding
Winters in Pacific in small numbers off Kamchatka and northern Japan and in varying numbers on the coast of North America from southern Alaska to California, vagrant to Baja California.
Rare in Europe but small numbers occur from southern Norway to the White Sea, off northern Scotland and on passage in the Baltic.
Vagrants recorded south to Spain and Italy.
Taxonomy
Habitat
Breeds on tundra lakes but coastal on passage and in winter.
Behaviour
Breeding
Begins late June-July and nests beside water often on an island or spit. Nest is a shallow scrape beside water or rarely a more substantial mound of vegetation.
Eggs: 2 (1 in replacement clutch), olive-brown, paler than Great Northern, with sparse black blotches (89 x 56mm). Incubated by both sexes for 29-30 days. Young tended by both sexes, feed themselves at 40 days and fly at about 72 days
Diet
Fish, also molluscs and crustaceans caught during 60-120 second dives.
Voice
Resembles Great Northern Diver but louder and harsher.
