[Gentoo]

I saw this article on wikipedia and it appears fairly recent. Does anyone know if the Mexican Duck has been reclassified as a full species?



The Mexican Duck (Anas diazi[1], and see below) is a dabbling duck in the genus Anas which breeds in Mexico and the southern USA. Most of the population is resident, but some northern birds migrate south to Mexico in winter.

It is a bird of most wetlands, including ponds and rivers, and usually feeds by dabbling for plant food or grazing. It nests usually on a river bank, but not always particularly near water.

Both sexes of this 51-56 cm length bird resemble a female Mallard, but with a slightly darker body. Mexican Duck is mainly brown, a blue speculum edged with white, obvious in flight or at rest. The male has a brighter yellow bill than the female.

The male has a nasal call, whereas the female has the very familiar "quack" commonly associated with ducks.

This species was formerly - and sometimes still is - considered a subspecies of the Mallard, as Anas platyrhynchos diazi (AOU 1983). This is by no means correct, however, as careful analysis of mtDNA control region sequence data - taking into account hybridization events - indicates it is the southwestern relative of the American Black Duck and shares a fairly recent common ancestry with this species (McCracken et al. 2001).

Including the Mexican Duck in the Mallard is a relict 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 offsprings, 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.

[edit] Conservation status

Although a species of least concern, the Mexican Duck is undergoing a slow but marked decline due to destruction of habitat and overhunting. It hybridizes with Mallards which are better-adapted to utilizing habitat altered by human activity and thus are spreading throughout this range. Concern has been expressed that this combination of factors may ultimately lead to the disappearance of the Mexican Duck as a recognizable taxonomic entity (Rhymer & Simberloff 1996, McCracken et al. 2001, Rhymer 2006), but fairly limited measures such as wetland preservation and preferential hunting of drake mallards would prevent this.

[Xenospiza]

The AOU has not split it (yet?)
I think a revision of its position is in place (as I hinted at in the "Anas rubripes" thread), but preferably not solely based on DNA, 'cause that's all statistic juggling with these ducks anyway!

[Chris Benesh]

Hi All,

Those with an interest in the ol' Mexican Duck may find this recent article of interest:

http://www.azfo.org/journal/mottled_duck.html

Chris

[AlexC]

Originally Posted by Chris Benesh

Hi All,

Those with an interest in the ol' Mexican Duck may find this recent article of interest:

http://www.azfo.org/journal/mottled_duck.html

Chris

Very interesting article, Chris!

I noticed it mentioned the "re-split" of Green-winged and Common Teal, but the AOU's current stance is lump - was it lumped AGAIN (my knowledge of taxonomy history is limited)?

[Gentoo]

Originally Posted by Chris Benesh

Hi All,

Those with an interest in the ol' Mexican Duck may find this recent article of interest:

http://www.azfo.org/journal/mottled_duck.html

Chris

Great article, very interesting. My guess is that it will be re-slpit sometime soon especially since they have determined that it is more closely related to Mottle Duck. Thanks for the info.

Mottled Duck
http://www.florida-tourism.net/flori...ed-duck-vr.jpg

Mexican Duck
http://www.azfo.org/journal/images/MexMallardRD.jpg

[Xenospiza]

Highly appreciated!

[Richard Klim]

Anas diazi Mexican Duck is split by Gill & Wright (on behalf of IOC) 2006 Birds of the World: Recommended English Names, but the introduction emphasises 'This is not primarily a taxonomic work'.

[Richard Klim]

...re-lumped with platyrhynchos by Gill & Wright (IOC) in 26 Aug 2007 updates, ref. www.worldbirdnames.org/updates.html, as one of several changes which re-align with AOU's position.

[Microtus]

The AOU lumped Anas crecca and carolinensis (Common and Green-winged Teals) in 1973 and they have been considered conspecific ever since. Similarly, diazi and platyrhynchos (Mexican Duck and Mallard) were also lumped in 1973 and have been considered conspecific ever since.