Ducks

Ducks are waterfowl in the order Anseriformes, in the family Anatidae, which also includes geese and swans. Ducks occur on all continents except Antarctica, and are widespread in many types of aquatic habitats. Almost all ducks breed in freshwater habitats, especially shallow lakes, marshes, and swamps. Most species of ducks also winter in these habitats, sometimes additionally using grain fields and other areas developed by humans. Some species of sea ducks breed on marine coasts, wintering in near-shore habitats. Most species of ducks undertake substantial migrations between their breeding and wintering grounds, in some cases flying thousands of miles, twice each year.

Ducks are well adapted to aquatic environments and are excellent swimmers with waterproof feathers, short legs, and webbed feet. The feathers are waterproofed by oil transferred from an oil gland at the base of the tail by the bill. Ducks eat a wide range of aquatic plants and animals, with the various species of ducks having long necks, wide bills and other attributes that are specialized for their particular diets. Most ducks obtain their food by either dabbling or diving. Dabbling ducks feed on the surface of the water, or they tip up to submerge their head and feed on reachable items in shallow water. Diving ducks swim underwater to reach deeper foods. Ducks have great economic importance as the targets of hunters and several species have been domesticated for agriculture. In general, duck populations have greatly declined world-wide, as a combined result of overhunting, habitat loss, and pollution.

Tree ducks (Dendrocygninae) are long-legged birds, and are much less common than most dabbling or diving ducks. Tree ducks tend to be surface feeders in aquatic habitats, but they also forage for nuts and seeds on land. Tree ducks have a generally southern distribution in North America. The most common North American species is the fulvous tree duck (Dendrocygna bicolor).

Stiff-tailed ducks (Oxyurinae) are small diving ducks with distinctive, stiffly-erect tails. This group is represented in North America by the ruddy duck (Oxyura jamaicensis).

Mergansers (Merginae) are sleek, diving ducks specialized for feeding on small fish, and have serrated bills, which apply a firm grip on their slippery prey. The most abundant species are the common merganser (Mergus merganser) and the red-breasted merganser (M. serrator).