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 fall. Divers and dabblers Wild ducks feed either by dabbling on the surface of the water, or by diving below the surface. Although Canvasbacks dabble at times, they are diving ducks because they usually dive for their food and because, like other divers, they have a special lobe on their hind toe that they use like a paddle in the water.
Mallards are hardy ducks, wintering regularly in southern Ontario and southern British Columbia.
Some will remain as far north as they can find open water. Even in Alaska, some birds are found throughout the colder months, and in Alberta, Mallards stay on the open waters of the North Saskatchewan River as far north as Edmonton. The great majority, however, migrate to the central and southern United States, where lakes and ponds are ice-free throughout the year. The Mallards are essentially freshwater ducks, although some may winter on coastal bays. Mallards are one of the first ducks to arrive back on the breeding grounds in spring.