Sabine's Gull
Sabine's Gull ( Xema sabini )
The Sabine's Gull ( Xema sabini ) is a species of bird in the family of gulls ( Laridae ) and is in the monotypic genus Xema. It is a breeding bird of hochartkischen tundra, which can be observed every year in Central Europe in limited numbers as Irrgast. Typically, such incursions are in strong west wind conditions. Thus, a total of 71 times Schwalbe gulls have been spotted in the German Bight and in the North Frisian Wadden Sea in 1997.
It was given its Latin name in honor of the astronomer Edward Sabine, the brother of the describer of Joseph Sabine.
Description
This about 33 centimeters long seagull has a strongly forked tail. Unmistakably it is in flight on the upper side by the black outer primaries and the broad white triangle behind them. In breeding plumage the head is slate gray and deducted against the white neck by a narrow black ring. In plumage the Sabine's Gull has a cloudy white head. In young birds the white tail edged with black. The rather short beak is black and wearing a yellow top. The legs have a gray color.
From unausgefärbten kittiwakes and little gulls, it differs in the deep forked tail and the lack of a dark band on the elytra. The voice is a screeching, screaming seeschwalbenähnliches. Even in flight affects the Sabine's Gull Seeschwalbenartig, because the body is raised with every wing beat something.
Occurrence
It inhabits the coastal waters of the Arctic and breeds in the tundra. Their breeding areas are located in northern Siberia, Spitzbergen, Greenland and northern North America. The main breeding areas in Alaska and northern Canada. Roving end specimens occasionally visit the coasts of Western Europe but, exceptionally, be cast by storms far into the interior of Europe. In winter, large amounts to the south in the area of the cold Benguela Current, other groups overwinter on the west coast of South America.
The Sabine's Gull is a long-distance migrant, their winter quarters are in the Atlantic and Pacific. The focus of the wintering region is above the Benguela front of the south or south-west Africa (25 ° S to 35 ° S). She considers herself while hardly near the coast. Even in the region of the Humboldt Current off the west coast of South America wintering gulls swallow. It is to breeding birds from Siberia, Alaska and probably the north-west of Canada.
Way of life
The Sabine's Gull feeds on insects and their larvae, crustaceans, small mussels and fish. The food is largely taken up in light air from the water surface. On the beach they are also found in running their food and occasionally looking at the sea and swimming for food.
The Sabine's Gull performs a monogamous marriage season and shows a high breeding site fidelity. It nests in colonies on swampy islands of the tundra and along the flat shores. The average of three eggs are incubated by both partners over a period of 23-24 days. The breeding success is largely determined by the predation by the arctic fox.
Stock
The stock of Schwalbe gulls was estimated at the beginning of the 21st century to less than 100,000 breeding pairs or 400000-700000 individuals. The European breeding population is only 100 to 500 breeding pairs.
Subspecies
The subspecies described in addition to the nominate Xema sabini sabini X. palaearctica see Stegmann, 1934 X. see tschuktschorum Portenko, 1939 and X. see woznesenskii Portenko be considered invalid in 1939.