Rowing ducks
| Rowing ducks | ||||||||||
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White-headed Ruddy Duck ( Oxyura leucocephala ) |
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| Systematics | ||||||||||
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| Scientific name | ||||||||||
| Oxyurinae | ||||||||||
| Swainson , 1831 |
The rowing ducks ( Oxyurinae) are a subfamily of the duck birds (Anatidae). These are specialized diving ducks, which are so different in many characteristics that they are not combined with the other ducks in the subfamily Anatinae in the system used here.
features
Of all duck birds, rowing ducks are the most adapted to aquatic life. Their legs are so far behind their bodies that they are much more awkward than other ducks when walking in the country. The feet are greatly enlarged. The tail, which is short and rectangular in other ducks, is long and pointed in the rowing ducks and is often upright. It serves as a rudder when diving. Since the tail feathers appear to wear out quickly, they are completely replaced twice a year. Rowing ducks also differ from other ducks in their beak. This is wide and high at the root and curved upward in the shape of a shovel at the front, the "nail" at the tip of the beak is curved downward in the shape of a hook. A broad, short body is typical of rowing ducks. The neck is short and comparatively thick. The wings are short and wide.
In all species there is a sexual dimorphism during the breeding season , in which the drake is more colorful and brightly colored than the female. After the end of the breeding season, the male takes on an inconspicuous color similar to that of the female. A much longer portion of the year remains in this plain dress than other ducks.
distribution and habitat
Rowing ducks are common on all continents except Antarctica. However, they only inhabit small parts of Europe, Asia and Africa, while the biodiversity is greatest on the American double continent. They can be found in all climates from the Arctic to the tropics. The habitat are rivers and lakes, sometimes brackish water, but no sea coasts.
nutrition
In terms of diet, rowing ducks hardly differ from diving ducks . They too dive to the bottom of water and dig for something to eat in the bottom mud with their beak. This can be vegetable matter or invertebrates. Mosquito larvae are the main food for most species.
Systematics
In the Kear system of ducks, rowing ducks are outside the subfamily Anatinae, to which most of the other ducks belong. Because of their many different characteristics, they are given the rank of their own subfamily. The genera and species according to Kear are:
- Genus Heteronetta
- Cuckoo Duck , Heteronetta atricapilla
- Genus Nomonyx
- Masked owl , Nomonyx dominicus (sometimes included in Oxyura )
- Genus Oxyura
- Ruddy Duck , Oxyura jamaicensis
- Argentine rowing duck , Oxyura vittata
- Australian rowing duck , Oxyura australis
- African rowing duck , Oxuyra maccoa
- White-headed Ruddy Duck , Oxyura leucocephala
Another species that is now extinct was described in 2005: Oxyura vantetsi , which was native to New Zealand.
The cuckoo duck is a very different species, as it lays its eggs in other birds' nests. The other rowing ducks are closely related, and the masked rowing duck is the sister species of the genus Oxyura .
supporting documents
literature
- PJ Higgins (Ed.): Handbook of Australian, New Zealand & Antarctic Birds , Volume 1, Ratites to Ducks, Oxford University Press, Oxford 1990, ISBN 0195530683
- Janet Kear (Ed.): Ducks, Geese and Swans. Oxford University Press, 2005, ISBN 0-19-854645-9 .
Web links
Single receipts
- ^ Higgins, p. 1140