Waterfowl: Order Anseriformes

The Order Anseriformes contains the turkey-sized screamers of South America, the odd Magpie Goose of Australia, and the familiar ducks, geese, and swans found worldwide.

The screamers are loud-voiced birds of the marshlands. They have long, slender toes with only rudimentary webs.  They have stout spurs at the bend of the wings. Unusual among birds, screamers lack uncinate processes. The males also lack a penis. The most peculiar feature of the screamers is a skin filled with small bubbles of air about a quarter of an inch thick, which produce a crackling sound when pressed; the function of this layer of air bubbles is unknown.

The Magpie Goose of Australia is an odd, black-and-white species with a long hind toe and partially webbed feet. It breeds in large colonies and presents food to its young, a unique behavior among waterfowl.

The ducks, geese, and swans are a diverse group of mainly aquatic birds that have webbed feet. A thin layer of skin covers the flattened, blunt-tipped bill, which bears a nail at the tip of the maxilla and fine lamellae along the margins of the maxilla and mandible. Waterfowl have a dense coat of firm, waterproof feathers, in distinct tracts, with a layer of down beneath. Many of these birds are colorful; the sexes of Temperate Zone ducks are often patterned differently. Some species are flightless.

Waterfowl vary in ecology from terrestrial grazers to deepwater divers and agile riders of ocean surfs and mountain streams. Bill form varies with diet, from those with lateral lamellae for straining microscopic food from mud and strong, broad bills for wrenching mollusks from rock moorings to narrow bills with sharp tooth-like serrations for capturing fish and short, blunt bills for grazing on field plants.

Male waterfowl, called drakes, have a penis. The drakes typically do not assist in incubation or care of the young, yet they are monogamous. In northern temperate species, drakes pair with hens on the wintering grounds and then return to their mate's birthplace.

Waterfowl:Order Anseriformes