| י255) שחפית עבת-מקור | ||||||||||
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:שחפית עבת-מקור . בינונית בגודלה ודומה לשחפית שחורת מקור . נבדלת ממנה במקורה הקצר, הגבוה והחזק הדומה למקור השחף . בקיץ כיפת הראש והעורף שחורים, הצואר לבן וחלקי הגוף העליונים אפרפרים תכלכלים . בחורף הראש לבן עם פספוס שחור עדין בעורף, וסוככות האוזן שחורות . המקור שחור וכן הרגלים הארוכות יחסית לאלה של שחפיות אחרות, שחורות . בית גידולה חופי ים, דיונות, ביצות מלוחות, נחלים ולגונות של מים מתוקים ניתן לראותה תרה אחר מזון בשדות עשב, ליד אגמים ושדות בפנים הארץ . ואפילו באזורים מדבריים למחצה . בארץ עוברת אורח שכיכה למדי בכל אזורי הארץ הנמוכים ... ואת השחף ... ויקרא י"א, 16 | ||||||||||
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Subspecies and Distribution.
G. n. nilotica Europe S to Mauritania and Tunisia, and E to Middle East, Kazakhstan, India to NW China. Winters from tropical Africa through Persian Gulf to India. G. n. addenda Manchuria and E China. Winters SE Asia. G. n. macrotarsa Australia. G. n. aranea New Jersey S to Texas, Cuba, Bahamas and Puerto Rico, and sparsely along Mexican coasts. Winters along Central American coasts and S to Brazil and Peru. G. n. vanrossemi California to Baja California and Sinaloa to Gulf of Tehuantepec. Winters S to Ecuador. G. n. groenvoldi coasts and river valleys from French Guiana to NE Argentina, Ecuador and N Peru. םםםםםםםםםםםםםםםםםםםםםםםםםםםםםםםםםםם םםםםםםםםםםםםםםםםםםםםםםםםםםםםםםםם | ||||||||||
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Descriptive notes.
Unique heavy-billed, long-legged tern whit slightly formed tail, broad wings and very pale body. 35-40 cm, 130-300 g, wingspan 85-100 cm. All black bill has sharp gonydeal angle, but no terminal hook, resembling that of small gull. Eye dark brown, crown and nape black, upperparts including rump pale grey, primaries slightly darker but wingtips whitish to pale grey. Tail and underparts white. Races differ mainly in size, especially of bill and also in color tone of upperparts. macrotarsa is largest race, especially in bill and feet. Habitat. Breeds on barrier beaches and dunes, salt marshes, and rivers and freshwater lagoons. Far more along coastal plains then in continental interiors, but also breeds on hypersaline lakes. Often feeds in large numbers on emerging insects over lakes, fields and grassland and even over semi desert. Winters on estuaries, lakes and salt-pans. Food and Feeding. More insectivorous than most other terns, prey including mainly grasshoppers, dragonflies, moths and grubs, also takes spiders, earthworms small reptiles and frogs, small fish and aquatic invertebrates. Flies slowly and then darts swiftly down to seize prey item from surface of ground, water or vegetation. Occasionally pirates food from other terns. Breeding. May-Jun in North America and Europe, Apr-May in India and Oct-Dec in Australia. Loosely to densely colonial. Nests on barren beaches, on sand, shell bars, dry mud, dykes, sea wrack, floating vegetation and nesting on roofs. 2-3 eggs, incubation 23 days. Chick white, usually unspotted. Parents attend young for 3 months. Returns to colony at 4 years old, but first breeding at 5 years. Movements. European birds disperse in all directions after breeding, then migrate across Spain, Italy and N Africa to W Africa. Others of nominate race winter E to India, and occasionally Indonesia, while E Asian breeders winter mostly in SE Asia. E North American birds migrate to SE USA and Gulf of Mexico. Some cross to Pacific and others winter along Costa Rican coasts. In E Australia, species nomadic. Status and Conservation. Not globally threatend. World population estimated at up to 55.000-60.000 pairs. Israel. In Israel subspecies G. n. nilotica. Common passage migrant over most lowlying areas. |
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