Sickle whistle goose
| Sickle whistle goose | ||||||||||||
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Sickle Whistler Goose ( Dendrocygna eytoni ) |
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| Dendrocygna eytoni | ||||||||||||
| ( Eyton , 1838) |
The Plumed Whistling Duck ( Dendrocygna eytoni ) is a kind from the subfamily of Whistling Ducks . It is part of the fauna of Australia and occurs there in the north and east of the continent.
According to the IUCN, the total population of sickle whistle goose is between 100,000 and 1 million animals. The species is classified as not endangered ( least concern ).
description
When fully grown, sickle whistle geese reach a body length of 40 to 60 centimeters and then weigh between 500 grams and 1.5 kilograms. The wingspan is 75 to 90 centimeters. Like the other species of whistling geese , they have long legs and large webbed feet. Heel and ankle have a net-like pattern, which is actually typical for geese . The sickle feathers that give it its name are particularly rich in contrast in perennial males. They clearly tower above the back. The iris is bright orange in the males and yellow in the females. Otherwise there is no noticeable sexual dimorphism . Adult birds go through the full moult after the breeding season. The moulting begins with the wings, followed by the moulting of the small plumage.
Newly hatched chicks are sepia brown on the upper side of the body. The underside of the body is cinnamon brown to gray. There is a bright, wide band in the neck. On the back, on each side of the body, a sand-colored longitudinal stripe runs from the base of the wings to the sides of the tail. The beak, iris and legs are gray. Young birds are monochrome, clay-gray, the red-brown front flank markings are still missing. The sickle feathers are not yet elongated and are pale clay yellow. The beak is lightened, but still without spots.
Outside the breeding season, sickle whistle goose rest in flocks, which can contain up to several thousand individuals, on the edge of wetlands near short-grassed pastures. During twilight and night they graze on the grasslands or dig on the edge of the wetlands. During the breeding season, they can usually be seen in pairs. The head and neck are carried very upright. They move slowly on the water, floating high on the water. In flight, they carry their heads lower than their backs and their feet dangle. The wing beat is slow.
Possible confusion
Whistling geese are not to be confused with any other species due to their upright posture. Their long neck and legs help differentiate them from other species of ducks. In flight they are noticeable by their utterances and the whistling smell of flight. The sickle whistle itself can only be confused with the wandering whistle . This is slightly smaller than the sickle whistle goose and darker. It also lacks the conspicuous sickle feathers on the sides of the body.
distribution and habitat
The sickle whistle goose occurs exclusively in Australia and lives there predominantly in the north and east. The range of the sickle whistle goose has expanded in southeast Australia since the 1950s. The development of agriculture in this region, which was accompanied by the creation of pastureland, dams and irrigated areas, offers the sickle whistle geese new habitats in this region. Random visitors occasionally reach New Guinea and New Zealand.
The habitat of sickle whistle geese is grassland of the tropical and temperate climate zone. They live both in coastal areas and inland. Its main area of distribution is the open grasslands in western Queensland. They also graze in pastures and hang out on the edge of water. In the regions with monsoon rains, they congregate near permanent bodies of water in the dry season. Sickle whistle geese can then be observed in large concentrations: In the dry season, migrations occur, which lead to thousands of these birds gathering on the banks and sandbanks of the not yet dried out waters. With the onset of the rainy season, these troops dissolve again and are spread over the grassland.
Sickpipe geese use a number of different habitats. The type of body of water is not important to them as they do not look for food in the water. They can be found near billabongs , ponds, swamps, rivers, dams, floodplains, and sewage fields.
nutrition
Sickle whistle geese feed almost exclusively on plants. Most of their food is found on land. With their goose-like beak they graze or pluck grass there. They usually move forward in dense flocks while grazing on land. Food intake takes place predominantly at night. Food that you find at the water's edge or on the water's surface is of less importance in your diet. When foraging in water, the individuals in a troop are more widely distributed than when foraging on land.
Reproduction
The sickle whistle goose is monogamous, the pair bond possibly exists until one of the two partner birds dies. During the breeding season, the pairs defend a territory. The size of the territory is not yet known, but it is certain that a couple is defending the immediate area around the nest. What is unusual is that the male takes care of the young. They are inhabitants of the tropical grasslands along the swampy plains. Sickpipe geese mainly feed on land. Food intake takes place predominantly at night. They graze or pluck grass there.
The exact breeding time is not known, but it is probably influenced by the respective geographical latitude and the onset and duration of the rainy season. The nest is built on the ground, while the sickle whistle geese choose places to build their nests that are high enough so that they are not flooded when the water level rises. This usually means that the nests are some distance from the shore line. The nests are only known from captivity until now. The nests have a diameter of 25 centimeters and are 10 centimeters deep. The exact size of the clutch is not known, but it is likely that a clutch consists of eight to fourteen eggs. In the case of sickle whistle geese kept in human care, the laying interval is about 48 hours.
Both parent birds are involved in the incubation of the eggs. The parent birds usually separate after a breeding interval of 24 hours. The breeding season is about 28 days.
Systematics
The more precise relationships within the whistling geese look like this:
| Whistling Geese (Dendrocygninae) |
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attitude
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The sickle whistle was imported as an ornamental fowl as early as the 19th century, but for a long time was one of the very rarely kept water birds in Europe. World first breeding was achieved in 1938 at a zoo in the USA, where two chicks grew up. Presumably, the European first breeding succeeded the zoo in Munich Hellabrunn. Only since the 1980s have sickle whistle geese been bred more regularly in Europe after a number of US-bred geese were introduced into Europe.
Individual references, literature and web links
literature
- T. Bartlett: Ducks And Geese - A Guide To Management. The Crowood Press, 2002, ISBN 1-85223-650-7
- PJ Higgins (Eds.): Handbook of Australian, New Zealand & Antarctic Birds , Volume 1, Ratites to Ducks, Oxford University Press, Oxford 1990, ISBN 0-19-553068-3
- Hartmut Kolbe: The world's ducks. Ulmer Verlag 1999, ISBN 3-8001-7442-1
Web links
- Dendrocygna eytoni in the endangered Red List species the IUCN 2008. Posted by: BirdLife International, 2008. Accessed January 31 of 2009.
- Videos, photos and sound recordings of Dendrocygna eytoni in the Internet Bird Collection
- BirdLife factsheet on the sickle whistle goose