Barnacle goose
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Barnacle Goose ( Branta leucopsis ) |
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| Branta leucopsis | ||||||||||||
| ( Bechstein , 1803) |
The barnacle goose or barnacle goose ( Branta leucopsis ) is a species of the genus sea geese ( Branta ) in the family of ducks (Anatidae). It is not divided into subspecies, but into three separate populations .
The barnacle goose used to breed only on the Russian Arctic coast. It has also colonized the Baltic Sea region since the 1970s and is now one of the breeding birds in Central Europe. However, it is still predominantly a winter visitor, which can usually be observed as a solitary bird or in small groups in the company of bean geese and white-fronted geese . At the beginning of the procession, however , they gather in huge swarms that can number up to 50,000 animals.
The characteristics of this species of geese include a close bond with the seashore, which is particularly pronounced in winter, as well as breeding in colonies of different sizes on rocky outcrops on the seashore and rivers. The colonies are often found in the immediate vicinity of bird of prey nests.
Appearance
Adults
The barnacle goose is a medium-sized goose with a size of 58 to 69 centimeters; their weight is about 1.5 to 2 kilograms. Typical features are the white face and forehead; The bill and neck are black. The underside of the body is silvery white. The wings are cross-banded in black and white. The contrast between the white face and the black head, neck and neck, was reminiscent of the traditional costume of Catholic nuns and gave it its name. The relatively short, round-looking neck and beak are also striking. Both sexes are of the same color.
chick
The downy chicks have an olive-gray back plumage. They are white at the bottom. However, there is also an olive-gray color field on the upper chest. The head and neck are whitish, the headstock is brown and a dark rein extends from the base of the beak to the eye. There are small white color fields on the back, the underside of the wings and at the end of the wings. Newly hatched downy chicks have dark bills with pink or cream colored nails. Legs, feet and webbed feet are gray.
The youthful dress of the barnacle geese already corresponds in color and pattern to the adult geese. It is, however, brown overall. Especially the shoulder feathers and the wing covers still have broad brown end bands. The white drawing of the face is still interspersed with individual black feathers. In their 1st annual dress, young geese that have not yet been moulted can only be distinguished from adult birds by the broad brown ends on the blankets.
voice
Barnacle geese are very vocal. Your call is mostly a single high-pitched, monosyllabic call that appears barking. It sounds like “ rrak ”, “ kak ”, “ guak ” or “ gock ”. From a distance the call can be mistaken for a dog barking. In the troops, the barnacle geese keep in touch with each other with softly muffled “ wachau ” or “ mach-mal ”.
When barnacle geese fly up, the instrumental sound is a creaking swinging sound.
Way of life
The barnacle goose is a migratory bird that usually moves south from its arctic breeding grounds in autumn and overwinters here in Central Europe . The flight paths of the barnacle goose are not genetically fixed, but are handed down in the various subpopulations.
Barnacle geese are sociable, outside of the mating and breeding season they live in more or less large flocks . In doing so, they often join other species of geese. Large flocks do not show any particular formation in flight, whereas smaller flocks of 20 to 40 animals form the typical V-formation . During the flight, contact calls can be heard constantly, which sound like "gäk gäk gäk" and can be vaguely reminiscent of barking dogs.
nutrition
Barnacle geese mainly live on short grass in winter , but also eat other plants that are native to salt and brackish water meadows, especially the Andel and samphire . In spring, the buds and kittens are also taken from willows , animal creatures such as various crustaceans , aquatic insects and probably also mollusks complete the food spectrum.
During the summer months, they feed mainly on polar lichens and mosses , which they scrape off the surfaces of the stones with the help of a sharp-edged curve at the end of the beak.
distribution
The barnacle goose is found in parts of the Western Palearctic . A total of three populations are distinguished: a) Spitzbergen , b) Greenland and c) Russian-Baltic population. The latter breed in large colonies in a wide area between Novaya Zemlya , Kolgujew and the Kanin Peninsula , but have also settled on Gotland and Öland since the 1970s and in Schleswig-Holstein , Lower Saxony and the Netherlands since the late 1990s . Central Europe is the fourth region and the only one in the middle latitudes that has a noteworthy breeding population with 2,200 to 2,800 breeding pairs.
Reproduction
Barnacle geese are usually very loyalty to their partners, but they mate again if the partner is lost. Usually several pairs breed together on high and inaccessible cliffs and rocks. The geese can only reach the nesting sites by flying.
The barnacle goose begins breeding in late May to early June. They return to their breeding areas a little later than the bean geese and white-fronted geese. Barnacle geese raise only one clutch per year. They breed in arctic valleys and prefer nesting sites there that are on rocky slopes. Only in exceptional cases do they breed on river islands. Barnacle geese usually nest in small colonies. The nests are usually at least two meters apart. The nests are often found in the middle of the guillemot colonies , in parts of the distribution area also between the thick-billed muzzles , kittiwakes and other sea birds. In large parts of the breeding area, the barnacle goose is very close to the clumps of peregrine falcons . This seems to be more pronounced, the greater the risk that arctic foxes will invade the colony. The nest is a flat hollow in the ground that is lined with only a little plant material. However, it contains large amounts of down and some other body feathers. The down is dark gray with a light center. They are darker than those of the short-billed goose and grayer and narrower than those of the eider .
The clutch usually consists of three to five eggs. They are creamy white in color, elliptical in shape and have a slightly rough, non-shiny surface. It only breeds the female, which begins with the brood after the last egg of the clutch has been deposited. The male is meanwhile near the nest. The incubation period is 24 to 25 days. The downy chicks flee the nest and are looked after by both parent birds. They fledge after about seven weeks, but initially stay near the parent birds.
Inventory development
The population of the barnacle goose was classified in the IUCN Red List of Threatened Species in 2016 as “ Least Concern (LC) ” = “not endangered”. From a low point in the 1950s, there was a spectacular increase in stocks. In 1970 there were 50,000 copies. The total population is currently estimated at 440,000 animals.
Individual evidence
- ^ Sächsisches Landesamt für Umwelt und Geologie (Ed.): Wild geese and swans in Saxony - occurrence, behavior and management. Dresden 2008, Publication as part of the public relations work of the Saxon State Office for Environment and Geology, p. 18, download as PDF (870 kB) from publications.sachsen.de
- ↑ Viktor Wember: The names of the birds in Europe - meaning of the German and scientific names. Aula-Verlag, Wiebelsheim 2007, ISBN 978-3-89104-709-5 , p. 80.
- ^ Hans-Heiner Bergmann, Hans-Wolfgang Helb, Sabine Baumann: The voices of the birds of Europe - 474 bird portraits with 914 calls and chants on 2,200 sonograms . Aula-Verlag, Wiesbaden 2008, ISBN 978-3-89104-710-1
- ↑ Uspenski, p. 33
- ↑ Hans-Günther Bauer, Einhard Bezzel and 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 , p. 55.
- ↑ Uspenski, p. 31
- ↑ Uspenski, p. 31
- ↑ Collin Harrison and Peter Castell: Field Guide Bird Nests, Eggs and Nestlings , HarperCollins Publisher, revised edition from 2002, ISBN 0007130392 , pp. 67 and 68
- ↑ Branta leucopsis in the endangered Red List species the IUCN 2016 Posted by: BirdLife International, 2016. Accessed February 27 2018th
literature
- Jeffrey M Black, Jouke Prop, Kjell Larsson: Wild goose dilemmas: population consequences of individual decisions in barnacle geese. Branta Press, Groningen 2007, ISBN 978-90-811501-1-8 .
- Hans-Heiner Bergmann , Helmut Kruckenberg, Volkhard Wille: Wild geese: travelers between wilderness and pastureland. G. Braun, Karlsruhe 2006, ISBN 978-3-7650-8321-1 .
- J. Madsen, G. Cracknell, Tony Fox: Goose Populations of the Western Palearctic. A Review of Status and Distribution . In: Journal of Applied Ecology . Vol. 36, No. 5, 1999, ISSN 0021-8901 , pp. 842-846.
- Erich Rutschke: Wild geese: way of life, protection, use. Parey, Berlin 1997, ISBN 978-3-8263-8478-3 .
- SM Uspenski: The wild geese of Northern Europe. Westarp Wissenschaften-Verlagsgesellschaft, Hohenwarsleben 2003, reprint of the 1st edition from 1965, ISBN 3-89432-7561 .
Web links
- Branta leucopsis in the endangered Red List species the IUCN 2008. Posted by: BirdLife International, 2004. Retrieved on January 4 of 2009.
- Videos, photos and sound recordings of Branta leucopsis in the Internet Bird Collection
- Barnacle goose feathers