White-backed Whistling Goose
| White-backed Whistling Goose | ||||||||||||
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White-backed goose ( Thalassornis leuconotus ) |
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| Systematics | ||||||||||||
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| Scientific name of the genus | ||||||||||||
| Thalassornis | ||||||||||||
| Eyton , 1838 | ||||||||||||
| Scientific name of the species | ||||||||||||
| Thalassornis leuconotus | ||||||||||||
| Eyton , 1838 |
The white-backed duck ( Thalassornis leuconotus ), and white-backed duck called, is one to the subfamily of Whistling Ducks corresponding type . It is systematically placed among the duck birds (Anatidae). Although it is closely related to the actual whistling geese (Dendrocygnini), it differs from them in its enormously specialized adaptation to diving. That is why in the past she was often placed with the rowing ducks (Oxyurini); but it is a case of convergent evolution . Sometimes a distinction is made between two subspecies, the African white-backed whistling goose ( Thalassornis leuconotus leuconotus ) and the Madagascar white-backed whistling goose ( Thalassornis leuconotus insularis ).
Appearance
White-backed Whistling Geese look short and stocky. The birds have brown speckled plumage, a black beak speckled with yellow, and green-gray legs. Males and females look alike. Both grow to about 18 inches long and weigh about 625 to 800 grams. They are anatomically well adapted to diving and can stay under water for about half a minute and cover up to 65 meters there. When swimming, the tail lies flat on the water.
nutrition
The white-backed Whistling Goose feeds mainly on parts of plants, especially seeds and leaves, but the young also eat caterpillars and insect larvae . The roots of water lilies are also sought after. They are brought to the surface by diving in shallow waters.
habitat
The white-backed whistling goose is distributed in southern Africa from Ethiopia to the Cape of Good Hope and West Africa from Chad to Senegal . Specimens of the insularis subspecies live exclusively on Madagascar . White-backed Whistling Geese prefer to live in calm waters with lush vegetation, such as reed lakes, swamps and river marshes, which offer them protection from predators.
Reproduction
Mated for life, both partners build the nest together during the breeding season , which can vary depending on the water level in the breeding area , which is usually created on small islands or in the reeds and is rarely lined with feathers . Often several pairs nest close together. The female then lays around four to ten light brown eggs . The brooding, which lasts about one month, and the subsequent rearing of the young is again carried out jointly by the males and females. After about two to four months, the young are fledged.
Systematics
The more precise relationships within the whistling geese look like this:
| Whistling Geese (Dendrocygninae) |
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Danger
The subspecies Thalassornis leuconotus insularis is endangered by hunting, loss of its habitat and introduced neozoa . The West African populations of Thalassornis leuconotus leuconotus are declining in the number of individuals, but are not yet considered to be threatened.
Individual references and other sources of information
Individual evidence
- ↑ for example in Kolbe, p. 73
literature
- T. Bartlett: Ducks And Geese - A Guide To Management . The Crowood Press 2002, ISBN 1-85223-650-7
- Hartmut Kolbe: The world's ducks . Ulmer Verlag 1999, ISBN 3-8001-7442-1
Web links
- Thalassornis leuconotus in the endangered Red List species the IUCN 2008. Posted by: BirdLife International, 2004. Retrieved on January 24 of 2009.