Yellow-billed duck
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Yellow-billed duck ( Anas undulata ) |
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| Anas undulata | ||||||||||||
| CF Dubois , 1839 | ||||||||||||
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The yellow-billed duck ( Anas undulata ) is a species from the duck family . It is one of the most common ducks in the open savannah landscapes of Africa .
Appearance
Yellow-billed ducks resemble mallards in size and shape . They reach an average weight of around 900 grams. The species shows only a slightly pronounced sexual dimorphism . The male is slightly larger and has a longer neck. The plumage on the head is more dotted and therefore looks a bit darker overall.
The downy dress of the yellow-billed chicks resembles that of the mallards.
Subspecies
Two further subspecies are distinguished within the species:
- the light yellow-billed duck ( A. and undulata Dubois, CF , 1839). It has a relatively conspicuous light gray feathered coat plumage and is the nominate species.
- the dark yellow-billed duck ( Au rueppelli Blyth , 1855), which, on the other hand, has a narrow, brownish fringed plumage.
Distribution, habitat and existence
Neither the light nor the dark yellow-billed duck are threatened in their population. The light subspecies settles on the lakes in the open savannah landscape of Africa. It is particularly common in eastern South Africa , where around 60,000 individuals overwinter.
The dark subspecies lives in small populations in the Ethiopian highlands and occurs there in the high mountains up to almost 4,000 meters above sea level. It also lives in East African waters.
Reproduction
Yellow-billed ducks prefer to build their nests on dry ground under bushes. The clutch comprises about ten to twelve cream-colored eggs that are incubated for 27 to 29 days. The chicks change from the dune dress to the youth dress from the 22nd day of life and show their first flight exercises in their tenth week of life. Young birds are sexually mature before they are even one year old.
food
Yellow-billed ducks mainly live on wild grasses and aquatic plants. In regions where arable farming is practiced, they also invade the grain fields towards evening. The food of the young birds also consists to a very large extent of insect larvae.
Yellow-billed duck as ornamental fowl
Yellow-billed ducks have been kept as ornamental poultry for more than 150 years . One of the first zoos to keep and breed this species was the London Zoo in 1853 . The zoo in Berlin achieved the first breeding within Germany in 1881 . As a rule, the light yellow-billed duck is kept.
Yellow-billed ducks are considered robust and hardy and easy to keep. However, since they resemble mallards , they met with little breeding interest, so that the animals that were kept in Europe are strongly influenced by inbreeding . For a long-term continuation of the breeding one is currently dependent on wild imports. Another problem is that yellow-billed ducks are very easy to cross with other ducks such as mallards. To prevent this from happening, keeping in aviaries is recommended. Aviary keeping also prevents yellow-billed ducks from crossing into European wild duck populations as captive refugees.
Yellow-billed ducks can be seen in the Hagenbeck zoo .
literature
- T. Bartlett, Ducks And Geese - A Guide To Management , The Crowood Press, 2002, ISBN 1-85223-650-7
- Hartmut Kolbe; Die Entenvögel der Welt , Ulmer Verlag 1999, ISBN 3-8001-7442-1
- Edward Blyth: Report of Curator, Zoological Department for April meeting 1855 . In: The journal of the Asiatic Society of Bengal . tape 24 , no. 3 , 1855, p. 252–281 ( biodiversitylibrary.org [accessed December 22, 2015]).
- Charles Frédéric Dubois: Ornithological gallery or pictures of all known birds . No. 1-22, 1835-1839 . JA Mayer, Aachen.
Web links
- Anas undulata in the endangered Red List species the IUCN 2008. Posted by: BirdLife International, 2008. Accessed on January 1 of 2009.
- Videos, photos and sound recordings of Anas undulata in the Internet Bird Collection