Tundra Bean Goose (Anser serrirostris)

Tundra Bean Goose

[order] ANSERIFORMES | [family] Anatidae | [latin] Anser serrirostris | [authority] Latham, 1787 | [UK] Tundra Bean Goose | [FR] Marabout chevelu | [DE] Ostliche Saatgans | [ES] Ansar Campestre | [NL] Toendrarietgans

Subspecies

Monotypic species

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

Averaging only slightly smaller than Greylag Goose but not so bulky, with less weight in the rear half of body. Large, tall, rather long-billed and long-necked, essentially brown goose, with very dark head and neck obvious in flight.
At long range and in poor light, difficult to separate from other grey geese but noticeable length of dark head and neck, upright stance, and uniform upperwing in flight, characteristic. High head carriage, bulk, uniform dark plumage tone, lack of forewing contrast, rather long, deep orange-marked bill, and orange legs all diagnostic at closer ranges. Confusion with large, dark individuals of Pink-footed Goose possible, but Bean Goose never shows grey upperparts and differences in bare-part colours afford certain distinction of typical birds.

Listen to the sound of Tundra Bean Goose

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

Copyright remark: Most sounds derived from xeno-canto


wingspan min.: 140 cm wingspan max.: 174 cm
size min.: 69 cm size max.: 88 cm
incubation min.: 27 days incubation max.: 29 days
fledging min.: 38 days fledging max.: 29 days
broods: 1   eggs min.: 4  
      eggs max.: 6  

Range

Eurasia : North

Habitat

Conspicuous differences in habitat characterize the various subspecies. More southerly breeders within west Palearctic (mostly nominate fabalis), extending in places to south of subarctic, unique among indigenous geese in nesting within dense coniferous forest or birch scrub. At times also on upland stony tracts with only scattered trees, usually near stream, pool or lake. Subspecies rossicus prefers more conventional Anser habitats on wet low tundra and Arctic Ocean islands, but habitat overlaps in some areas with nominate fabalis. Winter movements extend less far west than in other Anser; in normal winters, only small proportion reach grassy wetlands in oceanic climates. Fields under crops or fallow, steppe, floodlands, rivers, and coastal shallows used on passage and in winter.

Reproduction

Nests in low hummocks and banks free from snow and post-thaw flooding. often at base of tree or among bushes. Usually close to water but could be up to 1 km away. Normally well dispersed, though sometimes forming loose colonies. Previous year’s nests re-used with new lining. The nest consists of low mound of grasses, dead leaves, moss, and other vegetation, with shallow cup lined with down, particularly after laying. Building: mostly by female, though male may help, using material within reach of nest. The clutch size is 4-6, sometimes 3 or up to 8, in one brood per season. Eggs probably laid at 24-hour intervals. after hatching the eggshells left in nest.

Incubation continues for 27-29 days and is performed by females and starts after the lat egg is laid. She covers eggs with down when she is leaving the nest. The young are hatching synchronous. The young are immediately Self-feeding. Both parents care for young in defending them against predators. When still very young the chickens are brooded by female at night.

The young fledge in about 40 days. Young remain with parents during the first autumn and winter, migrating with them in spring but will be independent before they return back to breeding grounds. Age of first breeding normally 3 years.

Feeding habits

Grasses, cereal grains, and other agricultural crops; mainly by grazing on arable and pastureland in winter. On breeding grounds, feeds on green parts of plants, flowers and fruits, seeds, and rootstocks.

Video Tundra Bean Goose

httpv://www.youtube.com/watch?v=zg5jb07tE4g

copyright: ShenstoneBirder


Conservation

This species has a large range, with an estimated global Extent of Occurrence of 10,000,000 km2. It has a large global population estimated to be 800,000-840,000 individuals (Wetlands International 2002). Global population trends have not been quantified, but the species is not believed to approach the thresholds for the population decline criterion of the IUCN Red List (i.e. declining more than 30% in ten years or three generations). For these reasons, the species is evaluated as Least Concern.
Anser fabalis breeds in Fennoscandia and northern Russia, and winters patchily in
western, central and south-east Europe, which probably holds >50% of its global
wintering population. Its European wintering population is large (>390,000
individuals), and underwent a large increase between 1970-1990. Although there
were declines in a number of countries-notably the Czech Republic-during 1990-
2000, key wintering populations in Germany and the Netherlands were stable or
increased, and the species was stable overall.
Tundra Bean Goose status Least Concern

Migration

Migratory, winters mostly on coastal plains in NW and Central Europe and E Asia. Sporadically in more southern latitudes during cold winters.

Distribution map

Tundra Bean Goose distribution range map

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