Mexican duck
| Mexican duck | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Mexican duck ( Anas diazi ) |
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Anas diazi | ||||||||||||
| Ridgway , 1886 |
The Mexican duck ( Anas diazi ) is a duck bird that is counted among the swimming ducks. It is native to the southern United States and Mexico.
Appearance
General characteristics and possibilities of confusion
The Mexican duck is a large green duck. It reaches a body length of 51 to 56 centimeters. Their plumage is very similar to the female of the mallard . The body plumage, however, is a little darker and the face lighter, although the contrast is not as pronounced as in the dark duck . Since neither the range of the dark duck nor that of the similarly similar Florida duck usually overlaps with that of the Mexican duck, the species can be inferred from the distribution alone.
The Mexican duck has a greenish wing mirror with a narrow white band at the end. The tail feathers show little to no white. These two features are used to distinguish it from the mallard.
Details of the appearance
The Mexican duck has neither a seasonal dimorphism nor a pronounced sexual dimorphism . In comparison to the mallard, the blackish tail and the contrasting light sides of the face and neck are particularly striking. The male's beak is greenish yellow while that of the female is more olive green. The beak can be almost orange at the base. There are no dark markings on the upper beak. The plumage of not yet sexually mature young ducks looks a bit striped.
Basically, the plumage of the Mexican duck is very variable. In the distribution area there are also numerous hybrids, especially with mallards.
Distribution area
The Mexican duck used to be found from the southern United States to central Mexico. The range is now fragmented as a result of habitat changes. The breeding areas include the catchment area of the Rio Grande in New Mexico and Texas as well as the catchment area of the Gila River in southwest New Mexico and a small area on the border between Arizona and New Mexico.
In Mexico, the Mexican duck breeds mainly in the states of Chihuahua , Durango , Jalisco and México .
The Mexican duck is predominantly a resident bird. However, there is evidence that it is moving along the Rio Grande. In the Mexican state of Chihuahua, very few Mexican ducks can be seen in the winter months.
Systematics
The Mexican duck is very similar to the mallard and is occasionally classified as a subspecies of the mallard. Its plumage is very variable and it often crosses with the mallard and Florida duck. However, DNA analyzes that have been carried out in recent years indicate that it is a relatively young, but quite independent species. The research suggests that there is primarily a relationship with the dark duck . The classification of the Mexican duck to the mallard was mainly common in the middle of the 20th century. The Laysan duck and the Hawaiian duck , which today are largely undisputedly seen as independent species, were also assigned to the mallard during this time.
At the beginning of the 20th century, two subspecies were distinguished for the Mexican duck : Anas diazi diazi was considered a subspecies with the southern distribution area, Anas diazi novimexicana was assigned a distribution area in New Mexico. This classification is no longer considered valid today.
supporting documents
Individual evidence
- ↑ a b Kear, p. 521
- ^ McCracken , Kevin G .; Johnson, William P. & Sheldon, Frederick H. (2001): Molecular population genetics, phylogeography, and conservation biology of the mottled duck ( Anas fulvigula ). Conservation Genetics 2 (2): 87-102. doi : 10.1023 / A: 1011858312115 , PDF ( Memento of the original dated February 6, 2012 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. .
literature
- Janet Kear (Ed.): Ducks, Geese and Swans . Oxford University Press, 2005, ISBN 0198546459
- Hartmut Kolbe; Die Entenvögel der Welt , Ulmer Verlag 1999, ISBN 3-8001-7442-1