Bahamian Duck
| Bahamian Duck | ||||||||||||
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Female Bahamian Duck ( Anas bahamensis ) |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Anas bahamensis | ||||||||||||
| Linnaeus , 1758 |
The Bahamian duck ( Anas bahamensis ) belongs to the genus of real swimming ducks within the family of ducks .
features
The body of the Bahamian duck is elongated, the head is round and has a forehead bulge that is more pronounced in the male. The neck is of medium length and thin. The duck is mostly brown in color. The belly is light brown and has dark spots, the control feathers are white and the underside of the tail is reddish brown. The throat and cheeks are feathered white, the rest of the body is dark brown. The beak shaft is colored dark red, the front half of the beak is dark gray. The legs of the Bahamian duck are dark brown, the toes are grayish in color. The male shows a small feather bonnet on the top of his head when he is excited. In contrast to other duck species, the sexual dimorphism is hardly pronounced. The male is slightly larger, has a longer tail and more intense plumage than the female. In addition, the sexes differ in the voice: While the female is croaking, the voice of the male is a high-pitched, low whirring. Both sexes weigh around 500 grams.
Subspecies
There are three subspecies of the Bahamian duck:
- Northern Bahamian duck ( A. b. Bahamensis Linnaeus , 1758), which is the nominate form and lives in Central America and northeastern South America.
- Anas bahamensis rubrirostris Vieillot , 1816, is somewhat heavier than the nominate form, weighing around 700 g, and is common in southern South America.
- Anas bahamensis galapagensis ( Ridgway , 1890), who lives with several thousand individuals on the Galápagos island of Fernandina (Narborough).
Fossil evidence
In 1942 Franz Spillmann described the fossil duck species Archeoquerquedula lambrechti from the Young Pleistocene deposits of the Santa Elena Peninsula in Ecuador . When examining Spillman's type material in 1964 , Hildegarde Howard noticed great similarities with the bones of the Andean teal ( Anas flavirostris andium ). She synonymized the genus Archeoquerquedula with Anas and only granted Anas lambrechti a subspecies status . In 1979, Kenneth E. Campbell, Jr. compared topotypes of Anas lambrechti with the drawing Spillman had made of Anas lambrechti's skull and realized that the length of the eye socket is greater than the distance from the back of the eye socket to the parietal bone. In the duck species of South America, this condition only applies to the Bahamian duck. Therefore, Anas lambrechti is now considered a synonym for Anas bahamensis . Archeoquerquedula lambrechti was named after the Hungarian paleontologist Kálmán Lambrecht .
Occurrence
Bahamian ducks are distributed in isolated populations on the South American continent as far as Cuba . One of the subspecies , Anas bahamensis galapagensis , which is sometimes viewed as a separate species, is native to the Galápagos island of Fernandina (Narborough). There they live in brackish and salty shallow waters and in mangrove areas on the coast. However, they can also be found in nutrient-rich inland waters.
Way of life
Bahamian ducks feed on parts of plants, which they ingest by rooting.
The beginning of the reproduction depends on the respective distribution area. In the case of the Bahamian ducks native to the Caribbean, the breeding season begins in June and July, the ducks that live in the Lesser Antilles breed in August to November, with those in South America the breeding season is from May to October and with those living on the Galapagos Islands Populations in October to July.
The clutch consists of about 8 to 12 clay-colored eggs, which are incubated for 25 to 26 days. Newly hatched chicks weigh approx. 30 g. The duck leads the chicks, which show their juvenile plumage after about 20 days. The ducks are able to fly at around seven to eight weeks. They reach sexual maturity towards the end of their first year of life.
literature
- Hartmut Kolbe: The world's ducks. Ulmer, Stuttgart 1999, ISBN 3-8001-7442-1 .
- Carl von Linné: Systema Naturae per Regna Tria Naturae, Secundum Classes, Ordines, Genera, Species, Cum Characteribus, Differentiis, Synonymis, Locis . 10th edition. tape 1 . Imprensis Direct Laurentii Salvii, Stockholm 1758 ( biodiversitylibrary.org ).
- Robert Ridgway: Scientific results of explorations by the US Fish Commission steamer Albatross. No. I..Birds collected on the Galapagos Islands in 1888 . In: Proceedings of the United States National Museum . tape 12 , 1890, p. 101-128 ( biodiversitylibrary.org - 1889).
- Louis Pierre Vieillot: Nouveau dictionnaire d'histoire naturelle, appliquée aux arts, à l'agriculture, à l'économie rurale et domestique, à la médecine, etc. Par une société de naturalistes et d'agriculteurs . tape 5 . Deterville, Paris 1816 ( biodiversitylibrary.org ).
Web links
- Anas bahamensis in the endangered Red List species the IUCN 2008. Posted by: BirdLife International, 2008. Accessed on December 18 of 2008.
- Videos, photos and sound recordings of Anas bahamensis in the Internet Bird Collection
Individual evidence
- ^ IOC World Bird List Screamers, ducks, geese, swans
- ↑ Carl von Linné (1758), p. 124.
- ^ Louis Pierre Vieillot (1816), p. 108.
- ^ Robert Ridgway (1890), p. 115.
- ^ Franz Spillmann: Contribución al conocimiento de fósiles nuevos de la avifauna Ecuatoriana en el Pleistoceno de Santa Elena. In: Paul H. Oehser (Ed.): Proceedings of the 8th American Scientific Congress, Washington, 10-18 May 1940. vol. 4, American Scientific Congress, Washington DC 1942, pp. 375-389.
- ↑ Hildegard Howard: Fossil Anseriformes. In: Jean Delacour (Ed.): The Waterfowl of the World. Volume 4, 1964, pp. 301-302.
- ↑ Kenneth E. Cambell, Jr .: Non-passerine Pleistocene avifauna of the Talara Tar Seeps, Northwestern Peru. (= Life Sciences, Contributions (ROM ). Volume 118). 1979, p. 56.