Fish gull
| Fish gull | ||||||||||||
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Fish gull ( Ichthyaetus ichthyaetus ), in the moult from winter plumage to summer plumage |
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| Scientific name | ||||||||||||
| Ichthyaetus ichthyaetus | ||||||||||||
| ( Pallas , 1773) |
The fish gull ( Ichthyaetus ichthyaetus , Syn . : Larus ichthyaetus ) is a species of seagulls . This very large species breeds in the semi-deserts and steppes of Central Asia and overwinters mainly in southern Asia and on the Arabian Peninsula . In Central Europe the fish gull is an extremely rare exception.
features
With a body length of 58–67 cm and a wingspan of 146–162 cm, this species is almost as big as a black-headed gull , but looks slimmer and more long-winged than this. The gently sloping forehead is striking. Males weigh 1130–2000 g, females 960–1500 g. In the magnificent dress the head is black, above and below the eye there is a narrow white spot. The back and the upper wing covers are light gray, the rest of the trunk and the tail are white. The arm wings are light gray and have a wide white border. The hand wings are silvery white, the outer hand wings each show a narrow black subterminal band. The beak is three-colored; the base is dark yellow, followed by a narrow black band towards the tip and then a narrow reddish band, the tip is yellow again. The iris is dark, the legs are yellow.
In the plain dress , only the eye region, the top of the head and the back of the neck are diffuse blackish in color, and the red beak band is missing.
In youth clothing , the head in the area of the eyes and on the back of the head is colored diffusely brown, the white eye clips are already present. The back as well as the small and middle upper wing covers are scaly brown. The brown sides of the chest stand out clearly from the otherwise white body. A large, light gray wing field on the large arm covers is striking. The wings are predominantly dark brown-gray on the upper side, predominantly white on the underside and only brown-gray at the tips. The tail is pure white at the base and shows a broad, sharply defined black end band. The beak is yellowish pink and has a broad and sharply defined black tip; the legs are greyish pink. By the age of four the birds are colored.
The most frequent call is a deep croaking " kräh-uh ". The courtship call is a lined up, howling " kjauu-kjauu-kjauu ".
distribution and habitat
The distribution area of the species is in Central Asia and extends from the Caspian Sea and the Aral Sea to northwest China and western Mongolia . To the west of this area there are individual breeding occurrences as far as the Crimea and northeast of Volgograd .
The Pallas's Gull breeds in brackish lagoons and salt lakes and soda lakes in semi-deserts and steppes mainly in the lowlands, in the Tian Chan - and in the Altai Mountains but also in m high valleys until 1600-1700 height. During migration and in winter quarters, the species mainly lives on the coast of the sea, less often on large lakes and rivers.
food
The main food of the species are fish , which are usually captured by thrusting from a low shaking flight, but are also ingested dead or half-dead. However, rodents can also be the most important prey, especially in breeding colonies in steppe lakes . Smaller birds and bird eggs, reptiles , swarming insects and fishing waste are also used as food. Fish gulls also eat kleptoparasitic food, especially in winter, and try to steal their prey primarily from the terns and smaller gulls, but also from white claws and grebes. In contrast to other large species of seagulls, litter from rubbish tips and similar places is rarely used.
Reproduction
Fish gulls breed primarily in colonies that can range from 20 to 2000 pairs. Without exception, the colonies are located on islands that are far away from the shore and therefore inaccessible to ground predators and that usually have little or no vegetation. The nests are usually only 15–50 cm apart. The nest is occasionally just a hollow, delimited by a few blades of grass, but often a 5–15 cm high and 50–70 cm wide structure made of grass and salt plant blades . Depending on the geographical location, the eggs are laid from the beginning of April to mid-May. The clutch usually consists of 3, more rarely just one or two eggs. The eggs measure an average of 77.8 × 53.6 mm and are darkly spotted and dashed on a beige to olive-gray background. Both partners breed, but the female with a larger share. The breeding season is 23 to 29 days. The young birds fledge after about 45 days.
hikes
The fish gull is a migratory bird . Withdrawal from the breeding areas begins in early October. Some individuals already overwinter on the western edge of the Caspian Sea, but the majority of the population overwinters in an area that extends from southwestern Burma via Sri Lanka , Bangladesh , Pakistan , the Persian Gulf and the Red Sea to the southeastern Mediterranean . In Central Europe the species is an extremely rare exception, most of the observations obviously concern individual, widely roaming non-breeder.
Existence and endangerment
The IUCN gives the world population for 2002 roughly with 97,000–220,000 individuals. There is no reliable data on the development of the population, but there is also no evidence of a significant decline in the population; the IUCN therefore classifies the species as harmless.
literature
- Peter H. Barthel, Paschalis Dougalis: What is flying there? Franckh-Kosmos Verlags GmbH & Co. KG, Stuttgart 2006.
- E. Bezzel: Compendium of the birds of Central Europe. Nonpasseriformes - non-singing birds . Aula, Wiesbaden, 1985: pp. 514-515 and 760. ISBN 3-89104-424-0
- Urs N. Glutz von Blotzheim , Kurt M. Bauer: Handbook of the birds of Central Europe. Volume 8 / I: Charadriiformes. 3rd part: snipe, gull and alken birds. Aula, Wiesbaden 1999, ISBN 3-923527-00-4 , pp. 402-412.
- L. Svensson, PJ Grant, K. Mullarney, D. Zetterström: The new cosmos bird guide . Kosmos, Stuttgart, 1999: pp. 176-177. ISBN 3-440-07720-9
Web links
- Larus ichthyaetus in the endangered Red List species the IUCN 2008. Posted by: BirdLife International, 2008. Accessed October 13 of 2008.
- Feathers of the seagull