| י 347) טסית בתים | ||||||||||
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:טסית . כשמה כן היא, זו סנונית בעלת כושר תמרון מרהיב . סנונית בינונית בגודלה, ניכרת בגחונה ושתה הלבנים , כיפת ראשה וחלקי גופה העליונים צבועים בצבע כחול שחור מתכחתי , המקור קצר ושטוח, פיסת רגלה והאצבעות קצרות ועטויות נוצות לבנות . מיחד אותה משאר הסנוניות. הכנף חרמשית, מחודדת וארוכה . סוככות הכנף התחתונות אפורות. מזלג הזנב קצר בית גידולה משתרע מצפון אפריקה ומרבית איראסיה הפליארקטית, נעדרת ממרכז . אסיה, בחורף אוכלוסיתה חורפת בהודו ומזרח אסיה ובאפריקה שמדרום לסהרה . ניתן לראותה במורדות הרים סלעיים, בשדות מעובדים ובקרבת ישוב . מקננת בעיקר בצוקים וערים בארץ עוברת אורח שכיחה ברוב חלקי הארץ, מבקרת חורף נדירה בדרום ודוגרת קיץ . שכיחה למדי במרכז וצפון הארץ . 'הסנונית נזכרת בתלמוד במסכת שבת ע"ז ב | ||||||||||
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Subspecies and Distribution.
H. u. urbica Europe and N Africa east to W Siberia, Kashmir, and India. H. u. lagopoda C and E Asia from Yenisey basin, Altai mountains, Ussuriland, Kuril Is, and Japan. H. u. migrimentalis S-E China and Taiwan. םםםםםםםםםםםםםםםםםםםםםםםםםםםםםםםםםםם םםםםםםםםםםםםםםםםםםםםםםםםםםםםםםםםםםםםםםםםםםםםםםםםםםםם | ||||||||||
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Descriptive notes.
12-13 cm, 18-20 g, wingspan 26-29 cm. Medium size Hirundinidae, smaller than Barn Swallow, but head and body appear hardly less bulky due to proportionately shorter wings and tail. Uperparts blue-black with broad white rump. Underbody white. Flight less rapid and often at greater heigh than Barn Swallow. Sexes closely similar, some seasonal variation. Habitat. Breeds sparsely from shbarctic and boreal, and more abundantly through temperate to steppe and Mediterranean zones of west Palearctic, in oceanic as well as continental climates but usually avoiding extremes of temperature, and vulnerable to their effects on insect prey. In suitable weather, tends to forage in airspace above lowest levels favoured by Barn Swallow, but spends rather less of day in flight and, at least in north of range, seems to range less far from nest. Although transition from primitive rock-nesting to general use of buildings, bridges, and other artefacts is virtually complete over much of Europe, in some regions nesting on natural rock-faces with suitable surfaces and pitches remains locally common. Food and Feeding. Almost wholly flying insects, in breeding season, especially flies and aphids. Prey taken almost entirely by aerial pursuit, though many reports of birds feeding while perched on ground or trees-also from walls, rock faces, and reeds. Breeding. May-Apr in N-W and C Europe, May-Jun in northern and N-E Europe. Nest site, most frequent on outer walls of buildings, under caves or other overhang, also under bridges, culverts, etc, natural sites are on cliffs and outcrops, coastal and inland, also under overhangs. Colonial. Nest half-cup of mud pellets, down, feathers, and other light material. Cup formed against vertical wall and overhanging 'roof' with small oval entrance at top. Building by both sexes though male more active at start. 6-8 eggs, sub-elliptical, smooth and slightly glossy, white, very occasionally with fine, light red spotting. Incubation 14-16 days, by both sexes. Movements. Migratory. Winter records exist from Mediterranean basin and western Europe, north to Britain and Ireland, but west Palearctic and west Asian birds otherwise winter wholly in Afrotropics. Trans-Europe passage essentially south in autumn and north in spring, without strong S-W and N-E movement via Iberia. Hence birds from North Sea countries recovered more often in France than Spain, Scandinavian and German birds reach Mediterranean via southern France and Italy, and Finnish and east Baltic birds move in direction of Greece. Within Afrotropics, very wide scatter of observations indicates extensive size of winter range there, including humid zone north of equator, but such sightings few in relation to huge numbers of birds which must be involved. Status and Conservation. Not globally threatened. Fluctuating, marked decrease in Netherlands and Sweden but slight increase in Denmark. Euroopean populations estimated at some millions pairs. Israel. In Israel subspecies D. u. urbica common passage migrant, and rare winter visitor, also quite common local breeding summer visitor in northern and central Israel. |
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