| י 3 ) צוללן שחור-גרון | ||||||||||
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:צוללן שחור-גרון . ונדיר ממנו gavia immer קטן מהצוללן הצפוני .בתקופת החיזור , ראשו אפור, ובצוארו צבעי אפור ושחור מלווים בפסים שחורים ולבנים אנכיים .מצחו תלול פחות ומקורו עדין, בחורף בהירים הקודקוד והעורף יותר מהגב . בית גידולו אגמי מים עמוקים באזורי טייגות . בארץ מזדמן באקראי נדיר ביותר | ||||||||||
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Subspecies and Distribution.
G.a. pacifica extreme N & NW Nearctic; winters Pacific coast ofN America. G.a.arctica W Palearctic E to R L ena; winteres along coasts ofNW Europe, also in black, Caspian and Mediterranean Seas. G.a. viridigularis E Palearctic E of R Lena; winters NW Pacipic. | ||||||||||
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Descriptive notes.
58-73 cm; 1300-3400 g; wingspan 110-130 cm. Thicker neck and straighterlooking bill than G. stellata . Non-breeding adult brownish grey above, white below with noticeable white patch on flanks. Juvenile as non-breeding adult, withindistinct buffy scaling on upperparts.Race pacifica smaller with head and hind neck paler and bill tinner, viridigularis differs from nominate in green throat patch. Habitat. Breeds on fairly large, deep fresh water lakes, preferably with islets;more typically in taiga and boreal zone, less in arctic tundra than G. stellata. Winters on inshore waters along sheltered coasts, occasionaly inland. Food and Feeding Mostly fish, including gobies, herring, sprat, sculpins, cod, perch, trout, bleak occasionally crustaceans, molluscs, frogs, insects and sometimes some plant matter. Dives recorded to 3-6 m, averaging 45 seconds. Breeding. Starts May in S of range, dependent on spring thaw in N, Solitary; nestis heap ofplant matter near water's edge. 1-3 eggs, almost always2,incubation 28-30 days. chicks have sooty brown down, paler below; fledging60-65 days. Sexual maturity at 2-3 years lived over 27 years in thewild. Movements. Migratory and dispersive; generally moves southwards and towards sea after breeding.shunning ice-covered water; often forms flocks of 50 birds. Accidental S to Tropic of Cancer. Status and Conservation. Not globally threatened. World population probably large, in the order of several million birds,but generally decreasing throughout S of range. Over 1 million recordedon spring migration off california in 1980. Israel. In Israel subspecies G.a. pacifica . Accidental visitor. found at shores of Dead Sea and Eilat. |
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