| י233) חמסן זנבתן | ||||||||||
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:חמסן זנבתן . החמסן הקטן ביותר, אברות זנבו המרכזיות ארוכות במיוחד, מכאן שמו מקורו קצר, שחור ועדין משאר החמסנים, כנפיו ארוכות וצרות וחסרות את . הכתם הלבן המופיע אצל שאר החמסנים, ראשו קטן, רגליו אפורות, גונו בהיר . המופע הכהה נדיר ביותר. מעופו מרשים מזה של החמסן הטפיל . בית גידולו טונדרות ארקטיות והרריות, לאחר הקינון ימים ואוקיינוסים בארץ עובר אורח אקראי בחורף לאורך חוף ים התיכון . ומבקר סתיו ואביב נדיר במפרץ אילת | ||||||||||
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Subspecies and Distribution.
S. l. longicaudus Arctic and subarctic uplands of Scandinavia and Russia. Winters in subantarctic and offshore S South America and S Africa. S. l. pallescens Arctic Greenland, North America and Siberia. Winters in subantarctic and offshore S South America and S Africa.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. 50 cm (including tail streamers), 250-350 g, wingspan 105-110 cm. Smallest skua, with extremely long tail. Dark underwing with only bases of innermost two primaries white at base, and greyish tinge to upperparts also distinctive. Wholly sooty grey dark morph is extrimely rare. Moult and wear create barring pattern to underparts and tail coverts, and form a dark pectoral band so that winter plumage of adults is much more similar to that of Arctic Skua than is breeding plumage, though most confusion occurs in identification. Food and Feeding. Like S. pomarinus mainly lemmings during summer, caught by pouncing on them on the tundra surface. When micrrotine rodents are scarce, will take shrews, many insects, berries and small birds. Winter diet is largely unknown, but probably includes fish, some scavenging and kleptoparasitism. Usually solitary feeder, though will share tearing up prey with mate. Breeding. Jun. Scattered over tundra, highly territorial. Nest scrape unlied and inconspicuous. 2 eggs, but only one laid when food in short supply or by some inexperienced birds. Incubation 24 days. Chick has light grey brown down, leaves nest two days after hatching. Sexual maturity at 4 yars. Movements. Migratory. Because of highly pelagic so routes and winter distribution poorly known. Moves S in Aug-Oct, returning ot Northern Hemisphere in Apr-May. Rarely seen during coastal seawatches except with strong on shore winds. Rare vagrant inland. Status and Conservation. Not globally threatened. Total population several 100.000's of fairs. Israel. In Israel subspecies S. l. longicaudus. Accidental winter visitor to Mediterranean shores, and rare spring migrant at Eilat. |
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