The handsome Mallard is the best known wild duck in the world. It is distributed throughout North America, Europe, and Asia and has been introduced to many other parts of the globe.
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 male Mallard in breeding dress is unmistakable. The glossy head and upper neck are brilliant green, separated from the rich chestnut of the breast by a white collar. The rest of the under parts and the sides are light grey.
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. Its call is a loud quack-quack similar to that given by farmyard ducks. The call of the male is a softer, low-pitched rhab-rhab.
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 food of the Mallard depends on seasonal requirements for egg laying, moulting, or putting on body fat for migration and winter. Most food material is vegetation or invertebrates procured in the water or on the land. The bird feeds on emergent weeds, roots of plants that grow in shallows, and small swimming invertebrate animals or larval stages of insects that occur in a muddy bottom. On land it often turns to grain, and large flights of Mallards can be seen feeding in harvested grain fields in summer and autumn.
The female, accompanied by the male, now searches for a territory. Most often, she will choose a territory close to where she was born. Some females return year after year to the same site.
The female chooses the nesting site. It may be close by a pond, but is frequently at some distance and may 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 bush, or even in a tree hollow. 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 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 from her belly to line the nest. This grey down, with white centres, is pulled over the eggs when the duck is off to feed. It not only supplies warmth but hides the eggs from marauding 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. Four yellow patches relieve their clove-brown backs. Faces and under parts 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 pond or drain full of spring or rainwater, 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 her young. If surprised by a human or beast, 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, 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 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. All their flight feathers are shed at once, and for about a month the birds are flightless. They skulk 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 autumn 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 and loaf 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 wildfowler with arguably the best duck shooting.