Swallow gull
| Swallow gull | ||||||||||||
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Swallow Gull ( Xema sabini ) |
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| Systematics | ||||||||||||
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| Scientific name of the genus | ||||||||||||
| Xema | ||||||||||||
| Leach , 1819 | ||||||||||||
| Scientific name of the species | ||||||||||||
| Xema sabini | ||||||||||||
| ( Sabine , 1819) |
The swallow gull ( Xema sabini ) is a species of the gulls (Larinae) and is in the monotypical genus Xema . It is a breeding bird of the high Arctic tundra, which in Central Europe can be observed annually in small numbers as an irregular visitor . Such approaches are typical in strong westerly winds. In 1997, swallow gulls were sighted 71 times in the German Bight and in the North Frisian Wadden Sea.
It got its scientific name in honor of the astronomer Edward Sabine , the brother of the first descriptor Joseph Sabine .
description
This seagull, about 33 centimeters long, has a strongly forked tail. It is unmistakable in flight on the upper side by the black outer hand wings and the wide white triangle behind them. In the breeding dress the head is slate gray and set off against the white neck by a narrow black ring. When resting, the swallow gull has a cloudy white head. In young birds, the white tail is lined with black. The rather short beak is black and has a yellow tip. The legs are gray in color.
It differs from uncoloured kittiwakes and little gulls by the deeper forked tail and the lack of a dark band on the wing covers. The voice is a screeching, tern-like scream. The swallow gull also looks like a tern in flight, as the body is lifted a little with every flap of its wings.
Occurrence
It inhabits the coastal waters of the Arctic and breeds on the tundra . Their breeding areas are in northernmost Siberia, Svalbard , Greenland and northernmost North America. The main breeding areas are in Alaska and northern Canada. Wandering specimens occasionally visit the coasts of Western Europe, exceptionally they are blown far into the interior of Europe by storms. In winter, large numbers migrate south to the cold Benguela Current , while other groups overwinter on the west coast of South America.
The swallow gull is a long-distance migrant whose winter quarters are in the Atlantic and Pacific. The focus of the wintering region lies over the Benguela Current in front of the south or southwest of Africa (25 ° S to 35 ° S). She rarely stays near the coast. Swallow gulls also overwinter in the Humboldt Current region off the west coast of South America. These are breeding birds from Siberia, Alaska and probably also the northwest of Canada.
Way of life
The swallow gull feeds on insects and their larvae, crustaceans, small clams and fish. Most of the food is taken up by the surface of the water in easy flight. On the beach she also finds her food by running and occasionally she looks for food by swimming in the sea.
The swallow gull leads a monogamous seasonal marriage and shows a high loyalty to the breeding site. It nests in colonies on boggy islets on the tundra and along the flat coasts. The average three eggs are hatched by both partners over a period of 23 to 24 days. The breeding success is essentially determined by the predation by the arctic fox.
Duration
The swallow gull population was estimated at less than 100,000 breeding pairs or 400,000 to 700,000 individuals at the beginning of the 21st century. The European breeding population is only 100 to 500 breeding pairs.
Subspecies
The subspecies described in addition to the nominate form Xema sabini sabini X. s. palaearctica Stegmann, 1934, X. s. chuktschorum Portenko, 1939 and X. s. woznesenskii Portenko, 1939 are considered invalid.
supporting documents
literature
- Hans-Günther Bauer, Einhard Bezzel , Wolfgang Fiedler (eds.): The compendium of birds in Central Europe: Everything about biology, endangerment and protection. Volume 1: Nonpasseriformes - non-sparrow birds. Aula-Verlag Wiebelsheim, Wiesbaden 2005, ISBN 3-89104-647-2 .
- Roger Peterson, Guy Montfort, FAD Hollom: The Birds of Europe. 9th edition. Paul Parey Publishing House, Hamburg / Berlin 1968, ISBN 3-490-05518-7 .
Web links
- Distribution map with winter quarters
- Xema sabini inthe IUCN 2013 Red List of Endangered Species . Listed by: BirdLife International, 2012. Retrieved October 9, 2013.
- Swallow gull feathers
