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.
The back and wings of the bird are greyish brown, with a purplish-blue speculum, or wing patch, on the wing. The whitish tail has black above and below it. Two central black feathers that curve back above the tail give the breeding male its characteristic curly-tailed appearance. The male has a yellow bill and orange legs and feet.
The female Mallard is a much less colourful bird. Its back is mottled brown, its breast heavily streaked with buff and darker brown. It is best recognized by the white-bordered speculum on the wing, which is similar to that of the male. The female has an orange bill, sometimes blotched with black, and its legs and feet are orange.
Listen to the sound of Mallard
Copyright remark: Most sounds derived from xeno-canto
|wingspan min.:||81||cm||wingspan max.:||95||cm|
|size min.:||50||cm||size max.:||60||cm|
|incubation min.:||27||days||incubation max.:||28||days|
|fledging min.:||50||days||fledging max.:||28||days|
Even in the heart of many major cities, half-tame Mallards waddle ashore from park lakes to take food from the hands of visitors.
The Mallard is a typical member of the surface-feeding group of ducks, known as the dabblers. It is often seen in the tipped-up position with its tail held vertical. Although the bird can dive in an emergency, it rarely does so.
The nesting site may be close to a pond but is frequently at some distance and may even be far from water. Normally on the ground, the nest is little more than a depression lined with bits of rushes, grass, weeds, or other material close at hand. It is usually in good cover such as thick grass, or under a buckbrush, brier rose, or other prairie shrub. The eggs, which with different birds may vary in colour from dull green to almost white, are laid daily. Up to 15 may be deposited, but the usual number is between 8 and 12.
Incubation, or warming of the eggs until they hatch, does not start until the last egg has been laid. This ensures that all the ducklings will hatch at approximately the same time. During the laying period, and particularly in the early stages of incubation, the female sheds down, or fine feathers, from her belly to line the nest. This grey down, with white centres, is pulled over the eggs when the duck leaves the nest to feed. It not only supplies warmth but hides the eggs from crows, magpies, and other predators, which are quick to find uncovered eggs.
The female does all the incubating, which takes around 28 days. The ducklings emerge as handsome little balls of down. Their clove-brown backs are relieved by four yellow patches. Faces and underparts are also yellow, with the exception of a dark ear spot and a brown line through the eye.
Mallards may re-nest up to three or four times if their nests are destroyed. Each successive nest will have fewer eggs. However, Mallards do not raise more than a single brood of ducklings each year.
As soon as the ducklings are dry, the female leads them to the nearest water. This may be a long and hazardous journey. Although the female may have nested near a pothole or slough full of spring meltwater, much of this water may have evaporated, leaving nothing but drying mud. On overland trips, straggling ducklings may get lost in the grass or be picked up by predators.
The Mallard is an excellent mother, however. She will stop at frequent intervals to collect and brood, or warm, her young. If surprised by an intruder, she is likely to go flapping and squawking across the ground, as if injured. This feigned injury may not fool a human, but undoubtedly lures predators away.
Once on the water, the female leads her brood to feeding areas. The young find their own food, which at first probably consists of small crustaceans, or hard-shelled creatures, such as water fleas, insects, and tiny plants like duckweed. The young gradually lose their down and grow their feathers. In about 10 weeks they have assumed a plumage that is much like that of the female. By that time, the female has abandoned them. After the breeding season Mallards moult, or shed old feathers, into what is known as an eclipse plumage. The males are the first to undergo this moult.
The males remain on their territories for about the first 10 days of incubation. After that, they desert their mates. They move to larger marshes, where they lose their brilliant breeding plumage and become more similar to the hen, or female. All their flight feathers are shed at once, and for about a month the birds are flightless. They hide in the reeds until their new feathers are grown. When the females have left their broods, they too gather in the reeds to moult. They also become flightless, but the new plumage they assume is little different from the one they have shed. In the late fall the young gain the plumage of their respective sexes. The males, however, may not attain their full brilliance until their second year.
In late summer the birds gather in mixed flocks of young and old. Throughout much of the day they sit idly far from shore. As the grain ripens, the ducks make their flights to the feeding fields. These flights are usually made in early morning and late evening, but in dull, stormy weather may occur throughout the day. They provide the hunter with the best duck shooting.
This duck is breeding throughout northern Eurasia and North America. For practical reasons its populations of the European Union can be subdivided in three distinct sub-populations, separated by their wintering quarters. The first, totalling about 5000000 individuals and apparently stable, is wintering in the Atlantic regions from Denmark to the British Isles and Aquitaine. The second population is estimated at 1000000 individuals, and has nearly doubled during the last 20 years. It winters around the western Mediterranean, from Italy to Iberia. The third population is still estimated at 2250000 individuals, but has probably declined by 60-75% during the last 20 years. It winters in the Black Sea regions and the eastern Mediterranean, e. g. in Greece