Ducks, Geese and Swans (Anatidae)
The ANSERIFORMES (pronounced an-ser-ih-FOR-meez), one of the oldest avian orders, is composed of three families and includes the bizarre and noisy screamers of South America, the odd Magpie Goose of Australia, and the globally distributed swans, geese and ducks.
The swans, geese and ducks are grouped in the Anatidae (pronounced ah-NAH-tih-dee); a bird family with one hundred sixty-four species in forty-eight genera, various members of which can be found on all continents.
The Anatidae are represented in North America by sixty-nine species in twenty-three genera (including the extinct Labrador Duck). Members of this well known bird family include the graceful, long-necked swans, familiar geese of farm fields and golf courses, and the many species of ducks.
While all species are known for their association with aquatic habitats, Canada Geese are also known for their aggressive behavior when guarding their nests and young. After the breeding season, Canada Geese become better known for the "V" shaped flocks they form during migration.
Swans, geese, and ducks are large birds with long necks (longest in swans, shortest in ducks) and short tails. All species have webbed feet suited to their aquatic environments and distinctive flat bills - except for the mergansers with their thin, serrated bills ideally suited for catching fish.
Although swans and geese are mostly white, brown, and black, many ducks showcase several shades of grays, browns, and blacks combined with fine barring and streaking to result in a variety of beautifully patterned plumages for which females of the species are well known. Males in breeding plumage are more boldly patterned and often have iridescent blue or green on the head. Both sexes usually show a spot of color in the wing known as a "speculum".
Swans, geese, and ducks occur throughout North America wherever aquatic habitats are found. While geese and some ducks are often found along the shoreline, species that feed on underwater vegetation such as swans and dabbling ducks prefer calm water with depths suited to the length of their necks. In deeper waters, the mergansers, scoters, and diving ducks occur. Boldly-patterned Harlequin Ducks swim in the swift rivers and turbulent seashores of the Pacific Northwest and some areas of the northeastern U.S. and Canada.
A highly migratory family, most species migrate to open, ice-free water in sheltered bays and marshes of the southern United States with some reaching Mexico and Central America.
Members of the Anatidae flock together after breeding in large, multi-species groups at sites with good, safe foraging. At such sites, scoters, Canvasbacks, and other diving ducks dive for mussels in the deep sections while dabblers such as Gadwall and Northern Shovelers forage on the surface and in the shallows. On the shore, grazers such as geese and the American Widgeon forage on grass.
Populations of two Alaskan diving ducks, the Steller's and Spectacled Eiders, are threatened for reasons unknown; possible causes include changes in their habitats, nest predation by ravens and gulls, hunting, and the on-going effects of lead poisoning. The reasons why the Hawaiian Goose, and the Laysan and Hawaiian Ducks are endangered are much better understood; however after nearly going extinct, populations have stabilized but unfortunately don't have much room for growth in the limited amount of available habitat.
The white plumage of Snow Geese and Tundra Swans sometimes takes on a dirty, rusty-brown appearance. The birds aren't actually dirty but do show rust-colored highlights from foraging in the iron rich environments of the far north. Regarding the well-known description of the sound made by a duck as a "quack," duck species in North America also variously whistle, squeak, click, and grunt.