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. 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.
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|
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.
Video Tundra Bean Goose
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.