White-fronted Goose
Encyclopedia
The Greater White-fronted Goose (Anser albifrons) is a species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of goose
Goose
The word goose is the English name for a group of waterfowl, belonging to the family Anatidae. This family also includes swans, most of which are larger than true geese, and ducks, which are smaller....

. The Greater White-fronted Goose is more closely related to the smaller Lesser White-fronted Goose
Lesser White-fronted Goose
The Lesser White-fronted Goose is a goose closely related to the larger White-fronted Goose .It breeds in northernmost Asia, but it is a scarce breeder in Europe. There is a re-introduction scheme in Fennoscandia....

 (A. erythropus). In Europe it has been known as simply "White-fronted Goose"; in North America it is known as the Greater White-fronted Goose (or "Greater Whitefront"), and this name is also increasingly adopted internationally. It is named for the patch of white feathers bordering the base of its bill. But even more distinctive are the salt-and-pepper markings on the breast of adult birds, which is why the goose is colloquially called the "Specklebelly" in North America.

Description

Greater White-fronted Geese are 64 – in length, have a 130 – wingspan and weigh 1.93–3.31 kg (4.3–7.3 lb). They have bright orange legs and mouse-coloured upper wing-coverts. They are smaller than Greylag Geese
Greylag Goose
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....

. As well as being larger than the Lesser White-fronted Goose, the Greater White-fronted Goose lacks the yellow eye-ring of that species, and the white facial blaze does not extend upwards so far as in Lesser.

The male is typical larger in size, both sexes are similar in appearance – greyish brown birds with light grey breasts dappled with dark brown to black blotches and bars. Both males and females also have a pinkish bill and orange legs and feet.

Taxonomy

The Greater White-fronted Goose is divided into five subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...

. The nominate subspecies A. a. albifrons breeds in the far north of Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

 and Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

, and winters further south and west in Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

. In the far east of Siberia
Siberia
Siberia is an extensive region constituting almost all of Northern Asia. Comprising the central and eastern portion of the Russian Federation, it was part of the Soviet Union from its beginning, as its predecessor states, the Tsardom of Russia and the Russian Empire, conquered it during the 16th...

 east to Arctic Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

, it is replaced by A. a. frontalis, slightly larger and with a marginally longer bill, wintering in the United States and Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

.

Two other restricted-range races occur slightly further south in northern North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

: A. a. gambeli in interior northwest Canada, slightly larger still and wintering on the coast of the Gulf of Mexico, and the doubtfully distinct Tule Goose, A. a. elgasi, in southwest Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...

, largest and longest-billed of all, wintering in California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

. All these races are similar in plumage, differing only in size.

Finally, the very distinct Greenland White-fronted Goose, A. a. flavirostris, breeding in western Greenland
Greenland
Greenland is an autonomous country within the Kingdom of Denmark, located between the Arctic and Atlantic Oceans, east of the Canadian Arctic Archipelago. Though physiographically a part of the continent of North America, Greenland has been politically and culturally associated with Europe for...

, is much darker overall, with only a very narrow white tip to the tail (broader on the other races), more black barring on its belly, and usually has an orange (not pink) bill. It winters in Ireland
Ireland
Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...

 and western Scotland
Scotland
Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...

.

Recent ecological
Ecology
Ecology is the scientific study of the relations that living organisms have with respect to each other and their natural environment. Variables of interest to ecologists include the composition, distribution, amount , number, and changing states of organisms within and among ecosystems...

 studies suggest the Greenland birds should probably be considered a separate species from A. albifrons. Of particular interest is its unusually long period of parental care and association, which may last several years and can include grandparent
Grandparent
Grandparents are the parents of a person's own parent, whether that be a father or a mother. Every sexually-reproducing creature who is not a genetic chimera has a maximum of four genetic grandparents, eight genetic great-grandparents, sixteen genetic great-great-grandparents, etc...

ing, possibly uniquely among the Anseriformes
Anseriformes
The order Anseriformes contains about 150 living species of birds in three extant families: the Anhimidae , Anseranatidae , and the Anatidae, which includes over 140 species of waterfowl, among them the ducks, geese, and swans.All species in the order are highly adapted for an aquatic existence at...

.

Distribution

The North American midcontinent birds of the subspecies A. a. gambeli – which in 2010 had a fall population of about 710,000 birds – breeds from the Alaska North Slope
Alaska North Slope
The Alaska North Slope is the region of the U.S. state of Alaska located on the northern slope of the Brooks Range along the coast of two marginal seas of the Arctic Ocean, the Chukchi Sea being on the western side of Point Barrow, and the Beaufort Sea on the eastern.The region contains the...

 across the western and central Canadian Arctic. The Tule Geese of the American Pacific coast, which in 2010 numbered approximately 650,000 birds, nest in western Alaska. The midcontinent geese gather in early fall on the prairies of western Saskatchewan and eastern Alberta, spending several weeks feeding before heading to wintering areas near the Gulf of Mexico, into northern Mexico. The Pacific birds migrate south down the Pacific coast, staging primarily in the Klamath Basin
Klamath Basin
The Klamath Basin is the region in the U.S. states of Oregon and California drained by the Klamath River. It contains most of Klamath County and parts of Lake and Jackson counties in Oregon, and parts of Del Norte, Humboldt, Modoc, Siskiyou, and Trinity counties in California. The drainage basin...

 of southern Oregon and northern California and wintering, eventually, in California's Central Valley
Central Valley
Central Valley may refer to:*Central Valley *Central Valley, New York*Chilean Central Valley **Central Valley *Costa Rican Central Valley...

. The Tule Goose is very rare and has been since the latter half of the 19th century, presumably it was affected by destruction of its wintering habitat due to human settlement.

In the British Isles
British Isles
The British Isles are a group of islands off the northwest coast of continental Europe that include the islands of Great Britain and Ireland and over six thousand smaller isles. There are two sovereign states located on the islands: the United Kingdom of Great Britain and Northern Ireland and...

, two races overwinter: Greenland birds in Scotland
Scotland
Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...

 and Ireland
Ireland
Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...

, and Russian birds in England and Wales
Wales
Wales is a country that is part of the United Kingdom and the island of Great Britain, bordered by England to its east and the Atlantic Ocean and Irish Sea to its west. It has a population of three million, and a total area of 20,779 km²...

. They gather on farmland at favoured traditional sites, with a famous flock gathering at WWT Slimbridge
WWT Slimbridge
WWT Slimbridge is a wetland reserve managed by the Wildfowl and Wetlands Trust at Slimbridge, Gloucestershire, England. Slimbridge is halfway between Bristol and Gloucester on the estuary of the river Severn. The reserve was the first WWT centre to be opened, on 10 November 1946, thanks to the...

, Gloucestershire
Gloucestershire
Gloucestershire is a county in South West England. The county comprises part of the Cotswold Hills, part of the flat fertile valley of the River Severn, and the entire Forest of Dean....

, England. Greenland birds also overwinter in Ireland
Ireland
Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...

 and from late September and through the winter months, Ireland is home to almost 50% of the Greenland population of white-fronted geese.

A. a. albifrons and A. a. flavirostis are among the taxa to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA
AEWA
The Agreement on the Conservation of African-Eurasian Migratory Waterbirds is the largest of its kind developed so far under the Bonn Convention. It was concluded on 16 June 1995 at The Hague, the Netherlands and entered into force on 1 November 1999 after the required number of at least fourteen...

) applies.

Behaviour and ecology

Weather conditions are a key factor in the annual breeding success of White-fronted Geese. In the Arctic, the window of opportunity for nesting, incubating eggs, and raising a brood to flight state is open briefly, for about three months. Arriving in late May or early June, White-fronted Geese begin departing for fall staging areas in early September. This means that a delayed snowmelt or late spring storm can significantly reduce the birds' reproductive success.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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