| י231) חמסן רחב-אברה | ||||||||||
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:חמסן רחב-אברה : חמסן בינוני בגודלו, בעל שני מופעים, הבהיר . בהיר בגחונו וצוארו צהבהב בצידיו. הכהה: חום אפרפר וכהה כולו . בסיס כנפיו רחב ואברות זנבו המרכזיות בולטות בזנבו . ראשו גדול, המקור מגושם, רגליו קצרות ואת אצבעותיו מחברת פיסת עור . מעופו כבד. נוהג להיטפל לעופות ים אחרים ולגרום להם לפלוט את מזונם ולאוכלו . בית גידולו בעת הקינון טונדרות ארקטיות באזורים בהם נמצא למינג . לאחר הקינון משוטט ברחבי האוקינוסים . בארץ עובר אורח וחורף נדיר, לא שכיח באביב | ||||||||||
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Subspecies and Distribution.
Stercorarius pomarinus North Russia, Alska and Canada. Winters at sea, between Tropic of Cancer and equator, and around Australia .םםםםםםםםםםםםםםםםםםםםםםםםםםםםםםםםםםם םםםםםםםםםםםםםםםםםםםםםםםםםםםםםםםם | ||||||||||
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Descriptive notes.
48 cm, 500-850 g, wingspan 125-140 cm. Striking white wing panels. Adults occur in pale and dark morphs, but dark morph occurs at frequency of 20% in all populations. Moult leads to heavy barring appearance of underparts from late autumn, but vent area and flanks often barred even in summer plumage. Tail streamers often lost during summer. compared to S. parasiticus, has heavy bill, large head, large stout body and broad wings. Habitat. Breeds on Arctic tundra, where lemming numbers are high. Prefers low-lying moss tundra with pools. Marine outside breeding season, remaining somewhat coastal, especially in upwelling regions of the tropics and subtropics. Food and Feeding. While breeding, lemmings constitute over 90% of diet, will also take birds' eggs, young waders and gamebirds, some carrion and fish. In winter, feeds on fish, sometimes by kleptoparasitism, also kills small seabirds, and scavenges on carrion. Breeding. Jun. Widely scattered over tundra, highly territorial. Nest scrape unlined and inconspicuous. 2 eggs, incubation 26 days. Chick has dark grey-brown down. Sexual maturity at 3 years. Movements. Migrates ot winter in low latitude seas, chiefly N of equator, apparently including extensive migration over land. Departs from breeding areas mainly in Sep, with peak migration through temperate North Atlantic in Oct. Return migration in May, in small flocks. Status and Conservation. Not globally threatened. Total population is unknown, but there is no evidence of changes rn range or numbers. Israel. In Israel subspecies Stercorarius pomarinus. Rare winter visitor off Mediterranean shre, (mainly at open sea) and uncommon spring migrant and summer visitor in Gulf of Eilat. |
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