Chicken goose
| Chicken goose | ||||||||||
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Chicken Goose ( Cereopsis novaehollandiae ) |
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| Scientific name of the genus | ||||||||||
| Cereopsis | ||||||||||
| Latham , 1801 | ||||||||||
| Scientific name of the species | ||||||||||
| Cereopsis novaehollandiae | ||||||||||
| Latham , 1801 |
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The chicken goose ( Cereopsis novaehollandiae ) is a large, long-legged species of bird with a goose-like body shape with a head that is small in relation to the body and a conspicuous yellow-greenish wax skin on the upper beak. Chicken geese are among the most consistent grazing birds among the goose birds and only seek water surfaces when there is danger.
The chicken goose only breeds on the islands off the south coast of Australia. It was heavily hunted until 1960 because it was seen as a competitor to grazing cattle. In 1965 their population was only about 6,000 individuals. Since it was placed under protection, the population has recovered strongly so that it is no longer classified as threatened.
Appearance
Chicken geese reach a body length of 75 to 91 centimeters and are therefore about the size of a domestic goose. The wing span is 137 to 162 centimeters. Outwardly, males and females hardly differ from one another, but the males are heavier. In the chicken geese kept at Prague Zoo, the gander weighed an average of 5.2 kilograms, whereas the females weighed only 3.5 kilograms. The top of the head is white, the rest of the head and the neck are pale gray. The body plumage is ash gray with black wing tips. The legs are pale pink and the feet are black. The short black beak has a conspicuous yellow wax skin on the nose. The eyes are hazel brown. They go through the full moults after the breeding season. The moulting is initiated by the swing arm drop, then the control springs and the small plumage are changed.
The downy dress of newly hatched hen geese is gray-white. A black-brown stripe runs from the forehead over the top of the head and neck to the back. An eye stripe, the sides of the body and the wings are of the same color. The beak and feet are black. Fledglings that have fledged begin with the plumage and wear their first age-old dress at around six months. Young geese are a little darker than the adult birds and appear more darkly tinged with brown. The forehead and the middle of the head are then cream-colored to light gray. The beak wax skin has dark spots.
Adult hen geese are usually seen in pairs during the breeding season. Young birds not yet sexually mature form larger flocks and after the breeding season, flocks can contain several hundred individuals. Basically, these groups are only loosely socialized. On land they run with a rolling and lurching body movement, but they are very fast over short distances. Chicken geese are generally shy and seek the water in the event of disturbances. They are good swimmers and divers. In flight, the head is stretched far forward, the flight movements are strong and even and interrupted by gliding phases. While they are not very happy to call on land or on the water, they call regularly during the flight. Males let out a loud, choppy croak, while the females let out long grunts.
distribution
Chicken geese live exclusively in the south of the Australian continent and on the island of Tasmania . Its main area of distribution is the deserted islands between the Australian continent and Tasmania and the coastal strip in southeast Australia. Random visitors occasionally also reach New Zealand. In the Australian summer, the birds occasionally migrate to the mainland in search of food. The migratory movements are a reaction to the summer dry season, in which the grasses that are important for the chicken geese as food grow only very sparsely.
In New Zealand, a small number of hen geese were introduced to the South Peninsula in 1915. Chicken geese were occasionally observed until 1967, sometimes at a greater distance from the original release site.
habitat
The habitat of the hen goose is short-grassed marshes with sparse bushes and clumps of grass in salt or brackish waters, to which they are well adapted due to their ability to drink salt water. However, the animals avoid the water and usually only live on land.
The islands on which chicken geese breed are mostly small and very flat islands. The vegetation on the islands must be dense enough so that the nests can be created between protective vegetation. As a rule, there are feeding grounds with short grass in the immediate vicinity of the nesting sites. Stony and steep islands, on the other hand, are avoided by the hen geese.
food
Chicken geese feed primarily on grasses and their small seeds. They prefer grasses with a high nitrogen content and can therefore often be seen on irrigated fields, fertilized pastures and on the edges of wetlands.
They grasp blades of grass with the tip of the beak and tear them off by moving the head backwards. They spend most of the day eating. In the summer half of the year this is up to 12 hours a day, during the winter they graze between six and seven hours. Your digestive system is very simple, ingested food is only partially used and excreted after an average of 1.3 hours.
Antagonistic behavior can often be observed in feeding squads. Chicken geese react aggressively when they get too close. When threatening, the neck is bent sharply, the neck feathers are raised, the head is lowered and the folded wings are raised. Attacking chicken geese stretch their heads far forward and run or fly in the direction of the other bird. In direct disputes, they use the neck, beak, feet and wings.
Reproduction
A pairing relationship usually develops between the sexes beyond the breeding season in early autumn. The pairing usually begins at the age of 12 months. Most chicken geese are mated by the age of 24 months. They are usually 36 months old when they first brood. In exceptional cases chicken geese are only 24 months old and breed.
The breeding season falls in the Australian winter and thus in the growing season of the grasses on which the hen geese feed. Breeding begins usually between May and July. However, the geese usually arrive in February on the islands, which are their breeding grounds. The size of the breeding area depends on the quality of the respective habitat. In good habitats the area has an average size of 3,364 square meters, in less suitable habitats it is 5,237 square meters.
Unlike the real geese , the male helps in building a nest , but does not breed itself. The lined with down feathers ground nest of dry grass is vociferously defended against rival breeding pairs. It is preferably built in the area covered by clusters of grasses and bushes. Nests in the canopy of shrubs occur, but are rare. The female lays around four to seven cream-colored and rough-grained eggs. The laying interval is one to two days. The brood begins after the first egg is laid. During the breeding season, the female parent bird spends around seventy percent of its time on the nest. During this time he loses about 20 percent of his body weight. After an incubation period of around 35 days, the young hatch, which are usually fledged with the beginning of spring.
The predators that especially eat eggs and young birds include the black-billed gull and the tasmank crow . Numerous young birds also fall victim to feral domestic cats .
Systematics
Chicken geese show numerous primitive ( plesiomorphic ) characteristics within the geese , which means that they are quite isolated within the family group according to morphological characteristics. The noticeable features include the only partially webbed feet, the parent birds' oiling of the downy chicks with the secretion of the rump gland, mating on land and courtship behavior that does not have any elements that take place in the water.
According to morphological characteristics, the species is often placed in its own ( monotypical ) tribe Cereopseini (alternatively also written Cereopsini ).
Then the following phylogeny would result (only recent groups considered):
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According to genetic data, the South American Coscorobaschwan unexpectedly turned out to be closely related and would be the sister species . This is also taxonomically quite isolated in a monotypical genus Coscoroba .
Then the following relationships would result
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protection
The chicken goose is under protection. The extinction feared around 1960 could be prevented by protective measures, in particular a hunting ban. The IUCN estimates the total population at 16,000 to 18,000 animals and classifies the species as 
(= least concern - not endangered).
The recovery of the population has been due to the fact that pasture management has created more habitats suitable for the chicken goose. On the breeding islands, grazing cattle have contributed to the creation of open, short-grass areas. Extensive grazing is also considered necessary on the islands that are designated as nature reserves. On islands where grazing was stopped, these areas grew over again very quickly. However, there is still discussion about the damage that a dense collection of hen geese can cause on pastureland.
Attitude in Europe
Chicken geese were first imported to England in 1830/31. Shortly thereafter, breeding was successful in London Zoo . The Berlin Zoo keeps chickens geese since 1845th
Chicken geese also breed in Europe in the winter half-year. Reproductive activities begin when day lengths fall below 10 hours. The eggs are usually laid between November and January.
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 .
- 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 .
- PJ Higgins (Ed.): Handbook of Australian, New Zealand & Antarctic Bird. Volume 1. Ratites to Ducks. Oxford University Press, Oxford 1990, ISBN 0-19-553068-3 .
- Josep del Hoyo , Andrew Elliott, Jordi Sargatal (eds.): Handbook of Birds of the World . tape 1 : Ostrich to Ducks. Lynx Edicions, Barcelona 1992, ISBN 84-87334-10-5 .
Web links
- Cereopsis novaehollandiae in the Red List of Threatened Species of the IUCN 2008. Posted by: BirdLife International, 2004. Retrieved on January 19 of 2009.
- Videos, photos and sound recordings on Cereopsis novaehollandiae in the Internet Bird Collection
- BirdLife factsheet on the chicken goose
Individual evidence
- ↑ a b c d Kolbe, p. 130
- ↑ BirdLife Factsheet on the Chicken Goose , accessed April 9, 2011
- ↑ Higgins, p. 1194
- ↑ Higgins, p. 1194
- ^ Higgins, p. 1195
- ^ Higgins, p. 1195
- ↑ Higgins, p. 1196
- ^ Higgins, p. 1195
- ↑ Higgins, p. 1196
- ^ Higgins, p. 1197
- ↑ Higgins, p. 1198
- ^ Higgins, p. 1197
- ^ Higgins, p. 1197
- ^ Higgins, p. 1199
- ^ Higgins, p. 1199
- ↑ Bradley C. Livezey (1996): A Phylogenetic Analysis of Geese and Swans (Anseriformes: Anserinae), Including Selected Fossil Species. Systematic Biology 45 (4): 415-450. doi: 10.1093 / sysbio / 45.4.415 (open access).
- ↑ Carole Donne-Goussé, Vincent Laudet, Catherine Hänni (2002): A molecular phylogeny of anseriformes based on mitochondrial DNA analysis. Molecular Phylogenetics and Evolution 23: 339-356. doi: 10.1016 / S1055-7903 (02) 00019-2
- ↑ BirdLife Factsheet on the Chicken Goose , accessed April 9, 2011
- ^ Higgins, p. 1195
- ↑ Kolbe, p. 131