- Mallard (Anas platyrhynchos). Often poisoned by lead bullets. Has been poisoned in the West by foraging in temporarily damp lake beds. One of the most abundant ducks in the world today. The population on the Great Plains seems to have been permanently diminished from historical levels. The status of wild mallards is unclear due to the large feral populations.
- Mottled duck (Anas fulvigula). Has suffered more from encroaching human habitation (draining and destruction of marshland) and agriculture than from hunting. Interbreeding with feral mallards threatens the genetic purity of the species.
- American black duck (Anas rubripes). The population has decreased in response to aerial spraying for spruce budworm, destruction of habitat, acid rain, overhunting, clearing of forests, and competition with the mallard (with which it hybridizes).
- Gadwall (Anas strepera). This bird's range has been eastward. Settlement of the northern Great Plains took a relatively large toll on this species. Current populations vary each year, but the population does not seem to be diminishing.
- Green-winged teal (Anas crecca). Audubon wrote in 1840 that hunters in the West shot six dozen of these birds upon their first migratory arrival. Today the population appears stable.
- American wigeon (Anas americana). Population apparently stable. Since the 1930s, the breeding range has expanded into eastern Canada and the northeastern United States.
- Northern pintail (Anas acuta). This bird's nests in fields are often plowed up. It has also suffered lead shot poisoning. There is some indication of a decline in population since the 1960s, but the species is widespread and abundant today. Droughts on the northern plains may drastically reduce nesting success there.
- Northern shoveler (Anas clypeata). Population apparently stable.
- Blue-winged teal (Anas discors). Population apparently stable. Because this bird usually winters in Latin America, international cooperation is required to protect it.
- Cinnamon teal (Anas cyanoptera). Although the population has suffered by encroaching human habitation and agriculture (draining of wetlands and diverting water for irrigation), the current numbers appear stable.
- Ruddy duck (Oxyura jamaicensis). Current population is much less than historical levels, due mainly to shooting in the early 1900s and loss of breeding habitat.
- Masked duck (Oxyura dominica). Uncommon everywhere, but wide ranging in the tropics. Its secretive and nomadic behavior makes it hard to estimate this duck's population, or to protect it.
- Fulvous whistling duck (Dendrocygna bicolor). Population has declined in the Southwest in recent decades, but increased in the Southeast. There is some controversy over its effect on rice cultivation; some say it damages crops, others that it eats the weeds in the fields.
- Black-bellied whistling duck (Dendrocygna autumnalis). This bird is hunted mainly in Mexico. It will use nesting boxes. The population in the United States has increased greatly since the 1950s. Rare in Arizona before 1949, this bird in now a common nesting bird in that state.
- Wood duck (Aix sponsa). This duck has been hunted for its plumage, as a food source, and for its eggs. Development and forestry practices contributed to its decline. By the early 1900s, this bird was on the verge of extinction, but has since made a comeback. The wood duck readily uses nesting boxes.
- Canvasback (Aythya valisineria). The fact that breeding grounds have been reduced due to draining and cultivating of prairie potholes and freshwater marshes is probably responsible for the observed decline in numbers.
- Redhead (Aythya americana). Current population is well below historical levels, probably due to loss of nesting areas.
- Ring-necked duck (Aythya collaris). This duck's breeding range expanded eastward in the mid-1900s. The population suffered from lead shot poisoning. Since the 1930s, this bird has become a widespread breeder in eastern Canada and northern New England.
- Greater scaup (Aythya marila). Abundant. The fact that this bird congregates in large numbers in coastal bays in winter has caused concern that the species may be vulnerable to oil spills and other water pollution.
- Lesser scaup (Aythya affinis). Abundant, with relatively small fluctuations from year to year.
- Common eider (Somateria mollissima). Down from this duck, collected during incubation, is commercially valued. The taking of down, however, usually does not result in desertion of the nest. The populations have been increasing and stabilizing since 1930. Today this species is abundant, with a population estimated at several million. Local populations may be threatened by oil spills and other water pollution.
- King eider (Somateria spectabilis). Commercially valued as a source of down. Abundant in the Far North, with a population estimated to be several million.
- Spectacled eider (Somateria fischeri). Threatened or endangered. The population in the Yukon-Kuskokwim delta of western Alaska declined by 96% from 1970 to 1993. The status of the Siberian population is not well known.
- Steller's eider (Polysticta stelleri). Population in Alaska has declined significantly in recent decades.
- Labrador duck (Camptorhynchus labradorius). Extinct. The last known specimen was shot in 1875 on Long Island. Never abundant, this duck had a limited breeding range. Its extinction probably resulted from loss of habitat and hunting.
- Black scoter (Melanitta nigra). Population apparently stable. Birds at sea vulnerable to oil and other forms of pollution.
- White-winged scoter (Melanitta fusca). Population has declined in parklands and boreal forest of Canada, possibly due to advancing the hunting season to 2-3 weeks before some of the young can fly. Population today is apparently stable.
- Surf scoter (Melanitta perspicillata). Population apparently declined greatly in the early 1900s, but is now stable. Wintering populations are vulnerable to oil and other forms of pollution.
- Harlequin duck (Histrionicus histrionicus). The population appears stable in the Northwest. In the eastern part of North America, there has been a substantial decline over the past century.
- Oldsquaw (Clangula hyemalis). Abundant, with a population estimated to be in the millions. The tendency to congregate in large numbers makes it vulnerable to oil spills in northern seas. Large numbers of these birds are sometimes caught and killed in fishing nets.
- Barrow's goldeneye (Bucephala islandica). Population apparently stable. Will use nesting boxes.
- Common goldeneye (Bucephala clangula). Population apparently stable. Readily uses nesting boxes.
- Bufflehead (Bucephala albeola). Fairly common and widespread. Today less numerous than historically, due to unrestricted shooting in the early 1900s, and loss of habitat. Uses nesting boxes when cavities in trees are scarce.
- Common merganser (Mergus merganser). Population apparently stable in North America, possibly increasing in Europe.
- Red-breasted merganser (Mergus serrator). Population apparently stable.
- Hooded merganser (Lophodytes cucullatus). Population has declined due to loss of nesting habitat (large trees near water). Will use nesting boxes and cavities set up for wood ducks. Today the population appears to be increasing.
- Mandarin duck (Aix galericulata). Exotic. A native of Asia, this duck occasionally escapes, ending up in the wild.
- Spot-billed duck (Anas poecilorhyncha). An Alaskan stray. Native of Asia.
- Tufted duck (Aythya fuligula). A Western stray. The Eurasian counterpart of the North American Ring-necked duck. This bird occasionally reaches Alaska and the Pacific Coast from Asia, or the Northeast from Europe and Iceland.
See also ,!Eutrophication.
Bellrose, F.C. Ducks, Geese, and Swans of North America. Harrisburg, PA: Stackpole Books, 1976.
Forshaw, Joseph. Encyclopedia of Birds. New York: Academic Press, 1998.
Freedman, B. Environmental Ecology. 2nd ed. San Diego: Academic Press, 1995.
Godfrey, W.E. The Birds of Canada. Toronto: University of Toronto Press, 1986.
Johnsgard, P.A. Ducks in the Wild. Conserving Waterfowl and Their Habitats. Swan Hill Press, 1992.
Owen, M., and J.M. Black. Waterfowl Ecology. London: Blackie Pub., 1990.
Peterson, Roger Tory. North American Birds. Houghton Miflin Interactive (CD-ROM), Somerville, MA: Houghton Miflin, 1995.
Science EncyclopediaScience & Philosophy: Direct Variation to DysplasiaDucks - Dabbling Ducks, Bay And Sea Ducks, Economic Importance Of Ducks, Factors Affecting The Abundance Of Ducks - Tree or whistling ducks, Stiff-tailed ducks, Mergansers