Swan goose

Last updated

Swan goose
Anser cygnoides-Beijing.jpg
Anser cygnoides cygnoides in China
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Anseriformes
Family: Anatidae
Genus: Anser
Species:
A. cygnoides
Binomial name
Anser cygnoides
Subspecies

A. c. cygnoid(Linnaeus, 1758)
A. c. domesticus[ verification needed ] Chinese and African geese

Contents

Anser cygnoides distribution map.png
Breeding (northern areas) in orange and wintering (southern areas) ranges in blue
Synonyms
  • Anser cygnoides(Linnaeus, 1758) [orth. error]
  • Anas cygnoidesLinnaeus, 1758
  • Cycnopsis cygnoides( lapsus )
  • Cygnopsis cygnoides(Linnaeus, 1758)

The swan goose (Anser cygnoides) is a large goose with a natural breeding range in inland Mongolia, Northeast China, and the Russian Far East. It is migratory and winters mainly in central and eastern China. Vagrant birds are encountered in Japan and Korea (where it used to winter in numbers when it was more common), and more rarely in Kazakhstan, Laos, coastal Siberia, Taiwan, Thailand and Uzbekistan. [2] [3]

While uncommon in the wild, this species has been domesticated. Introduced and feral populations of its domestic breeds occur in many places outside its natural range. The wild form is also kept in collections, and escapes are not unusual amongst feral flocks of other Anser and Branta geese.

Description

The close-up of head Anser cygnoides (Germany,Heidelberg).jpg
The close-up of head

The swan goose is large and long-necked for its genus, wild birds being 81–94 cm (32–37 in) long (the longest Anser goose) and weighing 2.8–3.5 kg (6.2–7.7 lb) or more (the second-heaviest Anser, after the greylag goose, A. anser). The sexes are similar, although the male is larger, with a proportionally longer bill and neck; in fact the largest females are barely as large as the smallest males. Typical measurements of the wing are 45–46 cm (18–18 in) in males, 37.5–44 cm (14.8–17.3 in) in females; the bill is about 8.7–9.8 cm (3.4–3.9 in) long in males and 7.5–8.5 cm (3.0–3.3 in) in females. The tarsus of males measures around 8.1 cm (3.2 in). [2] [3] The wingspan of adult geese is 160–185 cm (63–73 in). [4]

At Moscow Zoo Swan Goose 01.JPG
At Moscow Zoo

The upperparts are greyish-brown, with thin light fringes to the larger feathers and a maroon hindneck and cap (reaching just below the eye). The remiges are blackish, as are the entire underwing and the white-tipped rectrices, while the upper- and undertail coverts are white. A thin white stripe surrounds the bill base. Apart from darker streaks on the belly and flanks, the underside is pale buff, being especially light on the lower head and foreneck which are sharply delimited against the maroon. In flight, the wings appear dark, with no conspicuous pattern. Uniquely among its genus, the long, heavy bill is completely black; the legs and feet, on the other hand, are orange as in most of its relatives. The eyes' irides are maroon. Juveniles are duller than adult birds, and lack the white bill base and dark streaks on the underside. [2] [3]

The voice is a loud, drawn-out and ascending honking aang. As a warning call, a similar but more barking honk is given two or three times in short succession. [3]

The karyotype of the swan goose is 2n=80, consisting of four pairs of macrochromosomes, 35 pairs of microchromosomes, and a pair of sex chromosomes. The two largest macrochromosome pairs as well as the Z (female) chromosome are submetacentric, while the third-largest chromosome pair is acrocentric and the fourth-largest is metacentric. The W chromosomes are acrocentric too, as are the larger microchromosomes, the smaller ones probably being telocentric. Compared to the greylag goose, there seems to have been some rearrangement on the fourth-largest chromosome pair. [5]

Ecology

It inhabits steppe to taiga and mountain valleys near freshwater, grazing on plants such as sedges (Cyperaceae), grasses (Poaceae) and water plants, [6] and rarely swimming. It forms small flocks outside the breeding season. In the winter, it grazes on plains and stubble fields, sometimes far from water. Birds return from the winter quarters around April, and the breeding season starts soon thereafter. It breeds as single pairs or loose groups near marshes and other wetlands, with nesting activity starting about May. The clutch is usually 5–6 but sometimes up to 8 eggs, which are laid in a shallow nest made from plants, placed directly on the ground, often on a small knoll to keep it dry. The precocial young hatch after about 28 days and become sexually mature at 2–3 years of age. Around late August/early September, the birds leave for winter quarters, where they gather in small groups to moult their worn plumage. [2] [3]

The swan goose was uplisted from Near Threatened to Vulnerable on the IUCN Red List in 1992 and further to Endangered in 2000, as its population is declining due to habitat loss and excessive hunting and (particularly on the Sanjiang Plain in China) egg collecting. But new research has shown it to be not as rare as it was believed, and consequently, it was downlisted to Vulnerable status again in 2008. Still, less than 500 pairs might remain in Russia, while in Mongolia numbers are unknown, though about 1,000 were seen at Ögii Lake in 1977. Favorite wintering locations in China are Lake Dongting, Lake Poyang, the Yancheng Coastal Wetlands and other locations around the lower Yangtze River, where some 60,000 individuals may be found each year – though this may be almost the entire world population. Until the 1950s, the species wintered in small numbers (up to about 100 birds annually) in Japan, but habitat destruction has driven them away.

Domestication

Though the majority of domestic geese are descended from the greylag goose (A. anser), two breeds are direct descendants of the swan goose: the Chinese goose and the African goose. These breeds have been domesticated since at least the mid-18th century – perhaps even (in China) since around 1000 BC. They vary considerably from their wild parent in appearance, temperament, and ability to produce meat and eggs; the most conspicuous feature is the prominent bill knob [3] [7] [8] and upright posture.

Charles Darwin studied goose breeds as part of his work on the theory of evolution. He noted that the external differences between Chinese geese and breeds descended from the Greylag goose belied a rather close relationship:

"The hybrids from the common and Chinese geese (A. cygnoides), species which are so different that they are generally ranked in distinct genera, [9] have often bred in this country with either pure parent, and in one single instance they have bred inter se." [10]

Conservation

The species is currently classified as an endangered species by the IUCN based on ongoing population declines and range losses, exacerbated by recent poor breeding success and unsustainable levels of hunting. [1] Total population was estimated as 36–43,500 individuals in 2023. [1]

Related Research Articles

<span class="mw-page-title-main">Goose</span> Common name for a group of waterfowl

A goose is a bird of any of several waterfowl species in the family Anatidae. This group comprises the genera Anser and Branta. Some other birds, mostly related to the shelducks, have "goose" as part of their names. More distantly related members of the family Anatidae are swans, most of which are larger than true geese, and ducks, which are smaller.

<span class="mw-page-title-main">Nene (bird)</span> Species of bird

The nene, also known as the nēnē or the Hawaiian goose, is a species of bird endemic to the Hawaiian Islands. The nene is exclusively found in the wild on the islands of Oahu, Maui, Kauaʻi, Molokai, and Hawaiʻi. In 1957, it was designated as the official state bird of the state of Hawaiʻi.

<span class="mw-page-title-main">Greylag goose</span> Species of bird

The greylag goose or graylag goose is a species of large goose in the waterfowl family Anatidae and the type species of the genus Anser. It has mottled and barred grey and white plumage and an orange beak and pink legs. A large bird, it measures between 74 and 91 centimetres in length, with an average weight of 3.3 kilograms. Its distribution is widespread, with birds from the north of its range in Europe and Asia often migrating southwards to spend the winter in warmer places, although many population are resident, even in the north. It is the ancestor of most breeds of domestic goose, having been domesticated at least as early as 1360 BCE. The genus name and specific epithet are from anser, the Latin for "goose".

<span class="mw-page-title-main">Greater white-fronted goose</span> Species of bird

The greater white-fronted goose is a species of goose that is closely related to the smaller lesser white-fronted goose. The greater white-fronted goose is migratory, breeding in northern Canada, Alaska, Greenland and Russia, and winters farther south in North America, Europe and Asia. It is named for the patch of white feathers bordering the base of its bill: albifrons comes from the Latin albus "white" and frons "forehead". In the United Kingdom and Ireland, it has been known as the white-fronted goose; in North America it is known as the greater white-fronted goose, and this name is also increasingly adopted internationally. 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.

<span class="mw-page-title-main">Taiga bean goose</span> Species of bird

The taiga bean goose is a goose that breeds in northern Europe and Asia. It is migratory and winters further south in Europe and Asia. This and the tundra bean goose are recognised as separate species by the American Ornithological Society and the International Ornithologists' Union, but are considered a single species by other authorities. The taiga and tundra bean goose diverged about 2.5 million years ago and established secondary contact c. 60,000 years ago, resulting in extensive gene flow.

<span class="mw-page-title-main">Pink-footed goose</span> Species of bird

The pink-footed goose is a goose which breeds in eastern Greenland, Iceland, Svalbard, and recently Novaya Zemlya. It is migratory, wintering in northwest Europe, especially Ireland, Great Britain, the Netherlands, and western Denmark. The name is often abbreviated in colloquial usage to "pinkfoot". Anser is the Latin for "goose", and brachyrhynchus comes from the ancient Greek brachus "short" and rhunchos "bill".

<span class="mw-page-title-main">Lesser white-fronted goose</span> Species of bird

The lesser white-fronted goose is a goose closely related to the larger white-fronted goose. It breeds in the northernmost Palearctic, but it is a scarce breeder in Europe, with a reintroduction attempt in Fennoscandia.

<span class="mw-page-title-main">Bar-headed goose</span> Species of bird

The bar-headed goose is a goose that breeds in Central Asia in colonies of thousands near mountain lakes and winters in South Asia, as far south as peninsular India. It lays three to eight eggs at a time in a ground nest. It is known for the extreme altitudes it reaches when migrating across the Himalayas.

<span class="mw-page-title-main">Snow goose</span> Species of bird

The snow goose is a species of goose native to North America. Both white and dark morphs exist, the latter often known as blue goose. Its name derives from the typically white plumage. The species was previously placed in the genus Chen, but is now typically included in the "gray goose" genus Anser.

<span class="mw-page-title-main">Emperor goose</span> Species of bird

The emperor goose, also known as the beach goose or the painted goose, is a waterfowl species in the family Anatidae, which contains the ducks, geese, and swans. In summer, the emperor goose is found in remote coastal areas near the Bering Sea in arctic and sub-arctic Alaska and the Russian Far East, where it breeds in monogamous pairs. It migrates south to winter in ice-free mudflats and coasts in Alaska, mostly the Aleutian Islands, and Canada's British Columbia, rarely reaching the contiguous United States. Listed as near threatened by the International Union for Conservation of Nature, the species' population is declining due to threats such as pollution, hunting, and climate change.

<span class="mw-page-title-main">Whooper swan</span> Species of bird

The whooper swan, also known as the common swan, is a large northern hemisphere swan. It is the Eurasian counterpart of the North American trumpeter swan, and the type species for the genus Cygnus.

<span class="mw-page-title-main">Chinese goose</span> Breed of domestic goose

The Chinese is an international breed of domestic goose, known by this name in Europe and in North America. Unlike the majority of goose breeds, it belongs to the knob geese, which derive from Anser cygnoides and are characterised by a prominent basal knob on the upper side of the bill. It originates in China, where there are more than twenty different breeds of knob goose.

<span class="mw-page-title-main">Cape Barren goose</span> Species of bird

The Cape Barren goose, sometimes also known as the pig goose, is a species of goose endemic to southern Australia. It is a distinctive large, grey bird that is mostly terrestrial and is not closely related to other extant members of the subfamily Anserinae.

<span class="mw-page-title-main">Ross's goose</span> Species of bird

Ross's goose is a white goose with black wingtips and a relatively short neck. It is the smallest of the three white geese that breed in North America. It is similar in appearance to a white-phase snow goose, but about 40% smaller. Other differences from the snow goose are that the bill is smaller in proportion to its body and lacks "black lips". The dark phase is extremely rare.

<span class="mw-page-title-main">Domestic goose</span> Common name for a bird

A domestic goose is a goose that humans have domesticated and kept for their meat, eggs, or down feathers. Domestic geese have been derived through selective breeding from the wild greylag goose and swan goose.

<i>Anser</i> (bird) Genus of birds

Anser is a waterfowl genus that includes the grey geese and the white geese. It belongs to the true goose and swan subfamily of Anserinae under the family of Anatidae. The genus has a Holarctic distribution, with at least one species breeding in any open, wet habitats in the subarctic and cool temperate regions of the Northern Hemisphere in summer. Some also breed farther south, reaching into warm temperate regions. They mostly migrate south in winter, typically to regions in the temperate zone between the January 0 °C (32 °F) and 5 °C (41 °F) isotherms.

<span class="mw-page-title-main">African goose</span>

The African or African Goose is a breed of domestic goose. It is one of two domestic breeds that derive from the wild species Anser cygnoides, the other being the Chinese; all other domestic geese derive from Anser anser. Despite the name, it is not from Africa but is of Asiatic origin. It is a large bird, among the heaviest of all goose breeds.

<span class="mw-page-title-main">Tundra bean goose</span> Species of bird

The tundra bean goose is a goose that breeds in northern Siberia. This and the taiga bean goose are recognised as separate species by the American Ornithological Society and International Ornithologists' Union, but are considered a single species by other authorities. It is migratory and winters further south in Asia. The taiga and tundra bean goose diverged about 2.5 million years ago and established secondary contact ca. 60,000 years ago, resulting in extensive gene flow.

<span class="mw-page-title-main">Bean goose</span> Species of bird

The bean goose is a goose that breeds in northern Europe and Eurosiberia. It has two distinct varieties, one inhabiting taiga habitats and one inhabiting tundra. These are recognised as separate species by the American Ornithologists' Union and the IOC, but are considered a single species by other authorities, such as the British Ornithologists' Union. It is migratory and winters further south in Europe and Asia.

References

  1. 1 2 3 BirdLife International. (2016). "Anser cygnoid". IUCN Red List of Threatened Species . 2016: e.T22679869A228564177. doi: 10.2305/IUCN.UK.2016-3.RLTS.T22679869A228564177.en .
  2. 1 2 3 4 Carboneras, Carles (1992). del Hoyo, Josep; Elliott, Andrew; Sargatal, Jordi (eds.). Handbook of Birds of the World. Volume 1: Ostrich to Ducks. Barcelona: Lynx Edicions. p.  581. ISBN   978-84-87334-10-8.
  3. 1 2 3 4 5 6 Madge, Steve; Burn, Hilary (1987). Wildfowl: an identification guide to the ducks, geese and swans of the world. Helm Identification Guides. London: Christopher Helm. ISBN   978-0-7470-2201-5.
  4. Ogilvie, M. A.; Young, S. (2004). Wildfowl of the World. New Holland Publishers. ISBN   978-1-84330-328-2.
  5. Wójcik, Ewa; Smalec, Elżbieta (2008). "Description of the Anser cygnoides Goose Karyotype" (PDF). Folia Biologica. 56 (1–2): 37–42. doi:10.3409/fb56_1-2.37-42. PMID   19055023.[ permanent dead link ]
  6. "Anser cygnoides (Swan goose)". Animal Diversity Web .
  7. Buckland, Roger; Guy, Gérard, eds. (2002). "Goose Production". FAO Animal Production and Health Papers. Vol. 154. Food & Agriculture Org. ISBN   978-92-5-104862-7. PDF fulltext [ permanent dead link ]
  8. Carol Ekarius (2007). Storey's Illustrated Guide to Poultry Breeds. North Adams, Massachusetts: Storey Publishing. ISBN   9781580176675.
  9. The swan goose had been separated in the monotypic genus Cygnopsis (alternatively spelled Cycnopsis) by Johann Friedrich von Brandt in 1836, some 20 years before Darwin wrote this. Cygnopsis cygnoides essentially means "Swan lookalike", Cygnopsis signifying "looking like a swan" and cygnoides "similar to a swan".
  10. Darwin, Charles (1859). On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life. London: John Murray. p. 253.