Greylag Goose
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 Western Greylag Goose (Anser anser anser)
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| Anser anser (Linnaeus, 1758) |
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The Greylag Goose, Anser anser, is a bird with a wide range in the Old World. It is the type species of the genus Anser.
It was in pre-Linnean times known as the Wild Goose ("Anser ferus"). This species is the ancestor of domesticated geese in Europe and North America. Flocks of feral birds derived from domesticated birds are widespread.
The Greylag Goose is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) applies.
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[edit] Physical appearance
The Greylag is a large goose, 74–84 cm long with a 149–168 cm wingspan. It has a large head and almost triangular bill. The legs are pink, and the bird is easily identified in flight by the pale leading edge to the wing. It has a loud cackling call, kiYAAA-ga-ga, like the domestic goose.
The western European nominate subspecies, A. a. anser, has an orange-pink bill and is slightly smaller and darker than the pink-billed Asian race, A. a. rubrirostris. Eastern European birds are often intermediate in appearance.
[edit] Reproduction and sexuality
Greylag geese tend to pair bond in long-term monogamous relationships. Most such pairs are probably life-long partnerships, though 5 to 8% of the pairs divorce and re-mate. Birds in heterosexual pairs may engage in promiscuous behavior, despite the opposition of their mates.
Homosexual pairs are common (14 to 20% of the pairs may be ganders, depending on flock), and share the characteristics of heterosexual pairs with the exceptions that the bonds appear to be closer, based on the intensity of their displays. Same-sex pairs also engage in courtship and sexual relations, and often assume high-ranking positions in the flock as a result of their superior strength and courage, leading some to speculate that they may serve as guardians of the flock. The orientations of the birds are generally flexible, as more than half of widowers re-pair with a bird of the opposite sex (Bagemihl, 1999).
[edit] Range and habitat
This species is found throughout the Old World, apparently breeding where suitable localities are to be found in many European countries, although it no longer breeds in southwestern Europe. Eastwards it extends across Asia to China.
The geese are migratory, moving south or west in winter, but Scottish breeders, some other populations in northwestern Europe, and feral flocks are largely resident. This species is one of the last to migrate, and it is thought that "greaylag" signifies in English "late", "last", or "slow", as in laggard, a loiterer, or old terms such as lagman, the last man, lagteeth, the posterior molar or "wisdom" teeth (as the last to appear), and lagclock, a clock that is behind time. Thus the Greylag Goose is the grey goose, which in England when the name was given, was not strongly migratory but lagged behind the other wild goose species when they left for their northern breeding quarters.
In Great Britain they much declined as a breeding bird, retreating north to breed wild only in the Outer Hebrides and the northern mainland of Scotland. However, since the 1930s and 1960s feral populations have been established elsewhere, and they have now re-colonised much of England. The breeding habitat is a variety of wetlands including marshes, lakes, and damp heather moors.
Within science, the greylag goose is most notable as being the bird with which the ethologist Konrad Lorenz first did his major studying into the behavioural phenomenon of imprinting.
[edit] North America
In North America, small populations of Greylag Geese descended from domesticated geese have become established, mostly in city parks and near humans. These geese usually exist as part of larger flocks of Canada Geese. The Greylag Goose can hybridize with the native Canada Goose, producing birds which, to say the least, can be puzzling to birders attempting to identify them.
[edit] Notes and references
- Bagemihl, Bruce (1999): Biological Exuberance: Animal Homosexuality and Natural Diversity: 479-481. St. Martin's Press. ISBN 0-312-19239-8
- BirdLife International (2004). Anser anser. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 11 May 2006. Database entry includes justification for why this species is of least concern
[edit] External links
- RSPB A to Z of UK Birds
- Greylag Goose videos on the Internet Bird Collection
- Confusing Domestic Geese - An article about Greylag geese in North America, with photos
[edit] Gallery
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 A Greylag Goose in St James's Park, London, England in May 2006 |
