Anas is a genus of dabbling ducks. It includes mallards, wigeons, teals, pintails and shovelers in a number of subgenera. Some authorities prefer to elevate the subgenera to genus rank. Indeed, as the moa-nalos are very close to this clade and may have evolved later than some of these lineages, it is rather the absence of a thorough review than lack of necessity that this genus is rather over-lumped. The phylogeny of this genus is one of the most confounded ones of all living birds. Research is hampered by the fact the radiation of the two major groups of Anas ? the teals and mallard groups ? took place in a very short time and fairly recently, roughly in the mid-late Pleistocene. Furthermore, hybridization may have long played a major role in Anas evolution, with within-subgenus hybrids regularly and between-subgenus hybrids not infrequently being fully fertile. The relationships between species are much obscured by this fact, and mtDNA sequence data is of dubious value in resolving their relationships; on the other hand, nuclear DNA sequences evolve too slowly to resolve the phylogeny of the subgenus Anas for example. Some major clades can be discerned. For example, that the traditional subgenus Anas, the mallard group, forms a monophyletic (in the loose sense, i.e. non-holophyletic) group has never been seriously questioned by modern science and is as good as confirmed (but see below). On the other hand, the phylogeny of the teals is very confusing. For these reasons, the dabbling duck lineages more distantly related to mallard group (which includes the type species of Anas) than the wigeons should arguably be separated in their own genera. These would include the Baikal Teal, the Garganey, the spotted black-capped Punanetta group, and the shovelers and other blue-winged species. Whether the wigeons, which are very distinct in morphology and behavior, but much less so in mtDNA cytochrome b and NADH dehydrogenase subunit 2 sequences, should also be considered a distinct genus Mareca (including the Gadwall and Falcated Duck) is essentially the one remaining point of dispute as regards the question which taxa should remain in this genus and which ones should not.
Listen to the sound of Mottled Duck
Copyright remark: Most sounds derived from xeno-canto
|wingspan min.:||70||cm||wingspan max.:||80||cm|
|size min.:||53||cm||size max.:||58||cm|
|incubation min.:||27||days||incubation max.:||28||days|
|fledging min.:||50||days||fledging max.:||60||days|
Site is in dense growth in marsh or prairie, sometimes on canal bank or in agricultural field, usually within 600′ of water. Where supported in dense clumps of grass, nest may be several inches above ground. Nest is shallow bowl of grasses, reeds, lined
with down and breast feathers.
Clutch 8-12, sometimes 5-13. Whitish to pale olive. Generally fewer eggs in later clutches. Incubation by female only, 24-28 days.
Young: Leave nest shortly after hatching; female leads them to feeding sites, and young feed themselves. Young can make short flights to escape danger at about 50 days; capable of sustained flight at 60-70 days. 1 brood per season.
Behavior: Forages in shallow water, mostly by dabbling with bill at mud just below water’s surface, occasionally by upending with tail up and head down. Young ducklings frequently dive underwater to feed; adults seldom do.
Video Mottled Duck
copyright: R. Shofield
This species has undergone a small or statistically insignificant decrease over the last 40 years in North America
Mostly non-migratory, but makes local movements in response to changes in habitat conditions. Some birds from western Gulf Coast may move southward along Mexican coast in winter.