The Mexican duck (Anas diazi) is a species of dabbling duck that breeds in Mexico and the southwestern United States.

Distribution and habitat

Most of the population is resident, but some northern birds migrate south to Mexico in winter. The species also occurs widely, but in limited numbers, in Colorado in all seasons and there are photographs of birds referable to this taxon from Utah, Wyoming, Nebraska, and Montana.

Mexican Ducks reside in almost all aquatic habitats.

Description

The bird has a length of 45–55 cm (17.7–21.6 in) and a weight of

The Mexican duck is mainly brown, with a blue speculum edged with white, obvious in flight or at rest. The male has a brighter yellow bill than the female.

Taxonomy

Including the Mexican duck in the mallard is a relic from the usual practice of much of the mid-late 20th century, when all North American "mallardines" as well as the Hawaiian and Laysan ducks were included in the mallard proper as subspecies. This was based on the assumption that hybridization, producing fertile offspring, is an indicator of lack of speciation.

Rather, in these birds it indicates a fairly recent allopatric radiation, which has not yet established solid barriers against gene flow on the molecular level; mate choice is conferred by cues of behavior and plumage in the mallardine ducks, and this, under natural conditions, has precluded a strong selective pressure towards establishment of genetic incompatibility.

Behavior

The Mexican duck primarily feeds on various seeds and aquatic plants.

== References ==<!-- Bird Conservation International (2002) 12:35–52. DOI: 10.1017/S0959270902002034 -->

  • American Ornithologists' Union (AOU) (1983): Check-list of North American Birds (6th edition). American Ornithologists' Union, Washington, DC.
  • Madge, Steve & Burn, Hilary (1987): Wildfowl : an identification guide to the ducks, geese and swans of the world. Christopher Helm, London. <small></small>
  • 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. <small></small> PDF fulltext
  • Rhymer, Judith M. (2006): Extinction by hybridization and introgression in anatine ducks. Acta Zoologica Sinica 52(Supplement): 583–585. PDF fulltext
  • Rhymer, Judith M. & Simberloff, Daniel (1996): Extinction by hybridization and introgression. Annu. Rev. Ecol. Syst. 27: 83–109. <small></small> (HTML abstract)

Footnotes

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