Baerente

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Baerente
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Bear Duck ( Aythya baeri )

Systematics
Order : Goose birds (Anseriformes)
Family : Duck birds (Anatidae)
Subfamily : Anatinae
Tribe : Diving ducks (aythyini)
Genre : Aythya
Type : Baerente
Scientific name
Aythya baeri
( Radde , 1863)

The Baerente ( Aythya baeri ), also known as the black-headed bog duck , is a relatively little-known diving duck from the duck family . It largely resembles the bog duck . The baerente, however, has a much larger beak. Their range is a small area in East Asia. The species is considered endangered. Exact populations of this duck are not known. In 2008 BirdLife International estimated the population size to be less than 5,000 individuals.

Its name refers to the German-Baltic naturalist Karl Ernst von Baer .

features

Baer ducks are 41 to 46 cm long. The male has a shiny green head, a brown chest, a dark gray back and brown flanks, to which the white belly stripes extends. The beak is blue-gray and becomes a little lighter in front of the black nail. The iris is straw yellow to white. When the drake is resting, the black-brown head and neck area is dull. The rump plumage is dull gray-brown. The flanks also appear darkened and the beak color takes on a darker blue-gray. The iris is unchanged from straw yellow to white even when it is at rest.

The female is gray-brown in color and has no noticeable differences in plumage from other female bog ducks. It can be distinguished from other female bog ducks mainly by its size and the chunky-looking beak. Their beak is dark gray. The iris is dark brown. Young bear ducks resemble the female regardless of gender. Their dark brown head and body plumage is dull. The light belly sides are still densely interspersed with gray-brown feathers. The flanks are only lighter in the lower part.

In flight, both sexes show a conspicuous white wing band as well as light underwings and a light belly.

distribution and habitat

The Baer's Pochard breeds in the Amur type region of Russia and in Manchuria in lakes and wetlands in the grasslands. North Korea and eastern Mongolia probably also belong to the breeding area. The breeding area is disjoint as a whole. However, the breeding sites are generally to be found in waters in the region of continental warm regions in summer. The duck prefers shallow lakes in open landscapes and avoids bodies of water in forest regions. Breeding waters have a wide belt of reeds and reeds, in which isolated areas of water are open. In winter the baerente moves to Japan , Thailand , Burma , Assam and Bangladesh . A few bear ducks also reach northeast India and overwinter there. However, most of the population overwinters in eastern China. There are probably fewer than 10,000 animals left with a decreasing population.

In the winter half year it occurs predominantly in similar habitats as during the breeding season. However, it can then also be found on brackish water lagoons, in river mouths and reservoirs. On the move, bear ducks mostly follow the course of the river. They can also be found on fast-flowing river sections during the migration.

Drawing of a bear duck

behavior

The Baerente prefers lakes in flat terrain rich in vegetation as a breeding area. Outside of the breeding season it gathers in small schools, while during the breeding season it can only be seen in pairs or in small family groups. The diet of the bear duck has so far been insufficiently researched. However, it eats both vegetable and animal material, which it probably dives up. In some regions rice is an important food crop for the bear duck.

Baer ducks reach their breeding area already mated. The return will take place in mid-March at the earliest and can drag on until mid-May. Most returnees arrive in their breeding areas during April. The nests are built in the thick belt of reeds. Bear ducks, however, also breed in colonies of gulls. The nests are compact structures made from plants around the nest. The nesting trough is laid out with medium gray nest dunes. The eggs are laid from late May to early June. The clutch consists of 10 yellow-gray eggs. They are incubated for 27 days.

Attitude in Europe

Baer ducks have so far only very rarely reached Europe. At the turn of the 20th century, bear ducks were kept at London Zoo. The drakes showed courtship behavior there. However, no eggs were laid. The British Wildfowl Trust received pairs of beard ducks at the beginning of the 1960s and first bred this species of duck in 1964. Breeding is also achieved in the USA and with European breeders. Probably due to inbreeding depression, the reproductive rate was low. It was only towards the end of the 1980s that bear ducks came back into western keeping. With these ducks it was possible to breed successfully. However, the problem with this species is that there are only very few and mostly closely related individuals living in the West.

literature

Individual evidence

  1. ↑ BirdLife Species factsheet (2008)
  2. ↑ Gooders and Boyer, p. 93.
  3. ↑ Kolbe, p. 278.
  4. ↑ Kolbe, p. 278.
  5. ^ Kear, p. 664.
  6. ↑ Kolbe, p. 278.
  7. ↑ Kolbe, p. 279.

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