African pygmy duck
| African pygmy duck | ||||||||||||
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African pygmy ducks |
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| Nettapus auritus | ||||||||||||
| ( Boddaert , 1783) |
The African pygmy duck ( Nettapus auritus ), also known as the African pygmy duck , is a small tropical duck bird that belongs to the swimming ducks. The distribution area of this species is limited to Africa and Madagascar .
Appearance
The African pygmy duck is one of the smallest ducks in the world. It reaches a body length of 27 to 32 centimeters and is not to be confused with any other duck species in its natural range due to its small body size. It differs from the likewise very small Hottentot duck , with whose distribution area there is overlap in Madagascar and in the extreme south, by its body color. The two species of ducks also use different habitats. On land she moves awkwardly due to her short legs. She is mostly on the water.
The males of the African pygmy duck have a white face with a conspicuous black eye spot. The beak is short and very high at the base of the beak and merges flat into the forehead so that the head has a slightly wedge-shaped profile. The black parting line runs to the nape of the neck. On the back of the head and the sides of the neck there is a large, powder-green patch that is bordered in black. The front neck is white. A narrow white band runs around the neck that is not completely closed at the nape of the neck. The lower neck, like the chest, is pale maroon, the flanks are bright maroon. The back is black and shimmers green. A wing mirror is missing. The belly is white. The beak is yellow with a black nail. The feet and short legs are dark gray to black. The iris is brownish red. A specific resting dress is missing. However, outside the breeding season, the male's face shows some gray spots. There are no studies on the course of moulting in the wild. In African pygmy ducks kept in human care, the wing moulting takes place before the chicks have fledged.
The females are dark brown on the forehead, crown and back of the neck. The iris is dark brown to black. The lower bill is yellow and the upper bill is brownish with a dark nail. The chest and flanks are dark maroon. The belly and feet are colored like the male. Young birds are like the female. With them, however, the eye stripe is wider or they each have a small black spot in the rein or eye area.
The chicks are black on top and have a light face. An eye stripe runs over the eye. There is a small black spot under the eye stripe as well as in the ear area. The underside of the body, a wing stripe and a spot on each side of the back are gray-white to creamy white. The beak and feet are blackish gray.
Distribution and existence
The African pygmy duck is native to sub-Saharan Africa and Madagascar. Their distribution ranges from Senegal and Ethiopia to the eastern subtropical regions of the Republic of South Africa. It was found in Zanzibar a long time ago and is a breeding bird on the island of Pemba . Madagascar is also part of its range, where it is particularly common in the western and northern lowlands.
The African pygmy duck is predominantly a resident bird. Train movements occur during dry seasons. During this time, swarms of more than 1,000 individuals can occasionally be observed in the South African Zululand . It is generally absent in arid regions and predominantly populates the lowlands. Basically, its range seems to expand after extended rainy seasons. It then also occurs in central South Africa. It is only occasionally seen in Chad and Sudan.
The African pygmy duck is a rare bird in most of its range. Large stocks can be found at Lake Tana in Ethiopia and in the Okavango Delta . The population is estimated at 20,000 to 30,000 individuals for West Africa. About 100,000 to 250,000 individuals live in eastern and southern Africa. About 15,000 of these occur in the Okavango Delta. In Madagascar the number of individuals is 5,000 to 10,000.
The population is decreasing in many areas of the distribution area. In Senegal, Kenya and Zimbabwe the species is considered threatened. Habitat changes, in particular a change in the aquatic plant population due to the introduction of exotic fish species such as the tilapia in Madagascar, lead to population decline . The African pygmy duck is also hunted in some areas. Due to the large distribution area and the sparse population density, it is difficult to establish suitable reserves for this species. However, it benefits from the establishment of national parks, which are primarily planned for the large African mammals, but generally offer them suitable habitats. Water retention basins can also represent suitable habitats for this species. However, you usually need nesting aids in the form of breeding holes.
Habitat and food
The African pygmy duck is found predominantly in standing or very slowly flowing freshwater. It is often associated with the white-backed whistling goose. The waters it populates have large floating vegetation. A population of water lilies seems to be the decisive criterion that leads to colonization by African pygmy ducks. Water lilies also play a major role in the diet of the other two species of pygmy ducks , the Australian pygmy duck and the Coromandel pygmy duck . Up to 99 percent of water lily seeds were found in stomach analyzes of the African pygmy duck. But it also eats the seeds of other plants, especially grass seeds of all kinds, small fish and invertebrates. The food composition is only subject to minor seasonal fluctuations. The chicks also eat the same food as the adult ducks from the start. Their ability to swim backwards, which is relatively unusual for ducks, seems to be an adaptation to bodies of water with a rich population of floating plants. Her feathers, which are otherwise very conspicuous, also offer her a good camouflage when she is resting between water lily leaves.
Various statements can be found in the literature as to whether this duck also submerges its food or mainly ingests it from the surface of the water. In captivity it has been observed that females bend plant stems with seed heads down to the surface of the water and call males to feed. This behavior has also been observed at least once in wild African pygmy ducks.
Reproduction
The courtship repertoire of the African pygmy duck includes, among other things, false attacks by the male on other drakes in the vicinity. The male either swims very quickly with his neck stretched out or flies low over the surface of the water. The other courtship gestures are less noticeable. The males swim around the female, turn their head towards her and present her with the green side of the head. The African pygmy duck is territorial during the breeding season. It also defends the breeding ground against the white-backed whistling goose . The pair bond appears to be strong and to last over several reproductive periods. The male defends the territory while the female breeds and also takes an active role in guiding the chicks.
The breeding time is very variable. It is triggered by rainfall. In Nigeria they breed mainly in the period July to August. In Uganda, the breeding season extends from June to October. In Madagascar, on the other hand, they breed predominantly in the months of December to April. They breed in tree hollows and prefer trees that are directly on the water. Occasionally they build their nests in the dense reed bed, under fallen trees or they use the abandoned nests of the hammer head . The actual nest is just a shallow hollow. It is not laid out with any nest material, only the plant material in the hollow is scraped up a little. The eggs are covered with a layer of down by the female when she leaves the nest. The eggs are creamy white. The full mesh comprises six to twelve. On average, a clutch consists of nine eggs. The breeding season is 21 to 23 days. The female breeds alone. The chicks hatch at the same time and are refugees. They climb out of the caves with the help of their sharp claws. They fledge after 38 to 42 days. According to Kolbe , the young birds can only fly at 56 to 63 days.
Keeping in human care
The first large number of African pygmy ducks reached the zoo park of Clères , France , in 1935 . Unlike the Australian dwarf duck and the Coromandel dwarf duck, which are considered to be very difficult , this species of duck settled in well there and could be kept for several years. However, there was no offspring.
Since 1960, small imports of this species of duck have made it to Europe and North America several times. The first breeding succeeded in 1975 in North America. The zoo in New York succeeded in breeding again successfully in 1979 and 1982. The zoo in Hong Kong was more successful, which raised a total of 26 chicks between 1985 and 1990. A more intensive keeping began only after 1984, after some hand-reared African pygmy ducks came to Europe. The first German breeding was achieved in 1990 by a private owner. Overall, breeding successes with this species are rare.
supporting documents
Individual evidence
literature
- Janet Kear (Ed.): Ducks, Geese and Swans. Oxford University Press, 2005, ISBN 0-19-854645-9 .
- Hartmut Kolbe: The world's ducks. Ulmer Verlag 1999, ISBN 3-8001-7442-1 .
Web links
- Nettapus auritus in the endangered Red List species the IUCN 2012. Posted by: BirdLife International, 2012. Accessed September 3, 2013.