Swan Goose (Anser cygnoides)

Swan Goose

[order] ANSERIFORMES | [family] Anatidae | [latin] Anser cygnoides | [authority] Linnaeus, 1758 | [UK] Swan Goose | [FR] Oie cygnoide | [DE] Schwanengans | [ES] Ansar Cisnal | [NL] Zwaangans

Subspecies

Genus Species subspecies Region Range
Anser cygnoides EU e

Genus

The waterfowl genus Anser includes all grey geese and sometimes the white geese. It belongs to the true geese and swan subfamily (Anserinae). 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 further south, reaching into warm temperate regions. They mostly migrate south in winter, typically to regions in the temperate zone. Numerous fossil species have been allocated to this genus. As the true geese are near-impossible to assign osteologically to genus, this must be viewed with caution. It can be assumed with limited certainty that European fossils from known inland sites belong into Anser. As species related to the Canada Goose have been described from the Late Miocene onwards in North America too, sometimes from the same localities as the presumed grey geese, it casts serious doubt on the correct generic assignment of the supposed North American fossil geese. The Early Pliocene Branta howardae is one of the cases where doubts have been expressed about its generic assignment.[citation needed] Similarly, Heterochen = Anser pratensis seems to differ profoundly from other species of Anser and might be placed into a different genus; alternatively, it might have been a unique example of a grey goose adapted for perching in trees.

Physical charateristics

Large goose with bi-colored neck and all black bill. Dark brown crown, nape and hindneck contrast strongly with pale creamy-brownish lower sides of head and foreneck. Adult has a whitish band from lores across forehead, bordering base of bill. Juvenile has duller crown, nape and hindneck and lacks whitish face-band. Greylag Goose A. anser has orange bill and lacks pale foreneck and whitish face-band.

Listen to the sound of Swan Goose

[audio:http://www.planetofbirds.com/MASTER/ANSERIFORMES/Anatidae/sounds/Swan Goose.mp3]

Copyright remark: Most sounds derived from xeno-canto


wingspan min.: 0 cm wingspan max.: 0 cm
size min.: 81 cm size max.: 94 cm
incubation min.: 27 days incubation max.: 30 days
fledging min.: 75 days fledging max.: 90 days
broods: 1   eggs min.: 5  
      eggs max.: 8  

Range

Eurasia : East. Anser cygnoides has its key breeding grounds in the border area between Russia, Mongolia and mainland China, with totals of 33,000 and 12,000 birds recorded in east Mongolia during surveys in 2003 and 20044 respectively. Other breeding sites include the lower reaches of the Amur river, north-western Sakhalin Island and Lake Khanka, Russia, western Mongolia and China. A poorly known population also appears to breed in eastern Kazakhstan, around Saisan-Lake and further east, but its current status is unknown. Breeding is suspected in north-eastern North Korea. It winters in North Korea, South Korea, central China, and occasionally in Japan and Taiwan (China).

Habitat

It breeds in wetlands in the steppe and forest-steppe zones, including river deltas, river valleys with meadows, the margins of brackish and freshwater lakes, and in mountainous areas along narrow, fast-flowing rivers. In winter, it occurs in lowland lakeside marshes, rice-fields, estuaries and tidal flats.

Reproduction

Nest is built in reedbeds on riverbanks, on grass hillocks in marshy meadows, and on grassy plateaux. Shallow nest of vegetation on the ground, lined with dry grass and down. They nest in scattered pairs or loose groups. Clutch size is 5-8 eggs. Incubation is done by female with male defending nesting ground. Newly-hatched are tended by both parents, They fledge after 10-11 weeks.

Feeding habits

Basically vegetarian, grazes often on dry land for grass, seeds and sedges.

Video Swan Goose

httpv://www.youtube.com/watch?v=8I5HE3JpyEo

copyright: Josep del Hoyo


Conservation

This species has been downlisted to Vulnerable because despite poor breeding success in recent years owing to drought, and considerable pressure from habitat loss, particularly owing to agricultural development, and unsustainable levels of hunting, comprehensive surveys in the wintering range have failed to detect evidence of declines of the magnitude predicted.
In Russia, the main threats are uncontrolled hunting, and drainage and ploughing of breeding and moulting habitats, but disturbance by people and cattle also cause high levels of chick mortality. In China, agricultural development at breeding grounds has resulted in wetland destruction and increased disturbance. Egg collection on Sanjiang plain (China), coupled with habitat loss to agricultural development, has probably resulted in a decline in the numbers of breeding Anatidae there of 90% in the last 30 years. Recent droughts on the breeding grounds have resulted in a number of years of poor recruitment. Hunting of waterfowl remains a serious problem in many parts of China. Its wetland wintering grounds are under increasing pressure from development and pollution
Swan Goose status Vulnerable

Migration

Recent research involving satellite tagging individuals has revealed that birds migrate in stages, stopping at a number of sites en route between breeding an wintering grounds. Birds gather in large flocks to moult in late July prior to migration.

Distribution map

Swan Goose distribution range map

Leave a Reply

Your email address will not be published. Required fields are marked *