Ducks, geese, and swans

(Anatidae)

Class Aves

Order Anseriformes

Suborder Anseres

Family Anatidae

Thumbnail description
Medium to very large-sized birds of predominantly brown, white, black, and metallic green colors, with a broad stocky body, webbed feet, and a flattened bill

Size
13–71 in (34–180 cm); 0.56–29.8 lb (255 g–13.5 kg)

Number of genera, species
41 genera, 147 species

Habitat
Marshlands, coastal waters, lakes, rivers, and streams

Conservation status
Extinct: 5 species; Endangered: 5 species; Critically Endangered: 5 species; Vulnerable: 11 species; Near Threatened: 7 species

Distribution
All continents except Antarctica

Evolution and systematics

The taxonomic history of the Anatidae began early with the work of F. Willughby and J. Ray who, in 1676, wrote the first comprehensive classification of aquatic birds. The systematics of the Anatidae have evolved considerably since then; however, at the beginning of the twenty-first century much controversy remains. The different classificatory schemes by J. Delacour, R. Verheyen, B. C. Livezey, and others, recognize anywhere from two up to 14 subfamilies. Here we follow P. A. Johnsgard who divided the Anatidae into seven subfamilies: the Anseranatinae (magpie goose), Dendrocygninae (whistling-ducks), Anserinae (geese and swans), Tadorninae (shelducks), Anatinae (wood ducks, dabbling ducks, pochards), Merginae (sea ducks), and Oxyurinae (stiff-tailed ducks).

The earliest fossils that can be identified as anseriform were those of Anatalavis rex. Two bones recovered from the Hornerstown Formation of New Jersey may date back to the Late Cretaceous or early Paleocene (80–50 million years ago). Similar bones, about 40 million years old, were found in England and helped identify these fossils as a member of the Anseranatinae. The most common anseriform in the fossil record is Presbyornis from the Paleocene and early Eocene (65–50 million years ago). According to S. L. Olson, Presbyornis may have looked like "a duck-like skull on the body of a long-legged wading bird." On the evolutionary tree of the anseriformes, Presbyornis branched off between the Anseranatinae and the other six subfamilies.

Physical characteristics

The Anatidae range in size from the minute African pigmy geese (Nettapus auritus), measuring only up to 13 inches (33 cm) and weighing no more than 0.51 lb (230 g), to the large trumpeter swan (Cygnus buccinator), which reaches a body length of 70.87 in (1.80 m) and a weight of 30 lb (13.5 kg). Some mute swans (Cygnus olor) may even weigh as much as 49.6 lb (22.5 kg). Plumages range from dull and inconspicuous, as in the greylag goose (Anser anser), to spectacularly colorful as in the mandarin duck (Aix galericulata).

Despite their variety, the Anatidae have a characteristic "Bauplan," or external morphology, which makes them readily distinguishable from all other groups of birds. The most obvious characteristics are a somewhat flattened bill with horny lamellae, a broad body, and partially webbed feet. The members of this family also share a hard process, the "nail," at the tip of the bill, long necks, a large preen gland crowned by a tuft of feathers, and a large external penis in males.

The structure of the bill and the lamellae are perfectly suited to the bird's diet and feeding methods. True geese are mostly herbivorous and feed by grazing. The bills are therefore strong, the "nail," used to grasp vegetation, is wide and the lamella stout and flat. Ducks that strain food particles from the water or mud have blade-like lamellae. These are tightly packed in filtering specialists such as shovelers. Shovelers also have a very broad, spatula-like bill to enhance straining efficiency. The "nail" is small in dabblers and filter-feeders. A

striking adaptation to feeding can be found in the mergansers (Lophodytes, Mergus). The backward pointing lamellae are serrated, almost tooth-like, and the horny bill is unusually narrow. Thus mergansers are able to get a firm grasp on slippery fish, their main diet.

The broad cross-section of the body is a result of powerful, bulging pectoral muscles needed for continuous beating of the narrow, pointed wings during flight. Except for a few island endemics and three species of steamerducks (Tachyeres brachypterus), all waterfowl are strong flyers.

Short thighs and tarsi form a powerful lever arm that makes waterfowl good swimmers. With the exception of the magpie goose (Anseranas semipalmata) and the Hawaiian goose (Branta sandvicensis), all Anatidae have webs between their front toes. Trapped air in the plumage and in the respiratory system provides buoyancy. Because of the wide body and relatively short legs, ducks and geese have a distinctive waddling gait.

Males of all ducks, geese, and swans have a copulatory organ which is evaginated from the cloaca for copulation. The sperm do not flow through a central canal of this erectile penis, as in mammals, but along grooves on the outside.

The palette of colors found in the Anatidae is very varied and spans all colors from red to blue and white to black. Nuptial plumages are also decorated by modified feathers or whole regions of the plumage. There are curled hoods, as in the muscovy duck (Cairina moschata) and crests as in the mergansers. A mane on the neck adorns the maned duck (Chenonetta jubata). Even more striking are the sickle feathers of the falcated teal (Anas falcata) and the elongated lancet-like flank feathers of the plumed whistling-duck (Dendrocygna eytoni). The wide, upward-bent inner vanes of the shoulder feathers of the mandarin duck (Aix galericulata) look like orange sails. In the male oldsquaw (Clangula hyemalis) the tail feathers are greatly elongated. Some members of the Anatidae are able to produce acoustic signals with their flight feathers. Lesser whistling-ducks (Dendrocygna javanica) produce a whistling sound, and golden-eyes (Bucephala) and the black scoter (Melanitta nigra) produce ringing sounds.

In some Anatidae, parts other than the plumage contribute to the decorative effect of the nuptial plumage. A highly colored fleshy hump at the base of the beak is present during the breeding season in many species, such as in some swans, scoters, and others. The bill may also be intensely colored in black, yellow, red, and blue.

In all ducks and geese, the flight feathers are molted only once a year. They are lost simultaneously so that the bird is incapable of flight for a short period of time. Only the magpie goose sheds its primaries sequentially and never loses its ability to fly. The contour feathers are usually molted twice a year, but three times in the oldsquaw (Clangula hyemalis). The "nest-down" on the abdomen grows before the onset of the breeding season. Before the clutch is complete, the incubating bird plucks down with its bill and pads the nest with it.

Distribution

From the Arctic Circle to Tierra del Fuego, South Georgia Island, New Zealand, and the Cape of Good Hope, ducks can be found on all continents except Antarctica.

The magpie goose lives in Australia and New Guinea. The Dendrocygninae are mostly restricted to tropical or subtropical regions of North, Central, and South America, the West Indies, Africa, Asia, and Australia. They are absent in Europe. The Anserinae are limited in their distribution to mostly temperate and Subarctic regions and, with the exception of a few vagrants, are absent from Africa. The Hawaiian goose lives only on Hawaii Island. The Tadorninae have South American (10 species), African (five species), and Australasian representatives (five species). The Anatinae (86 species) are cosmopolitan. With 33 resident and nonresident species, Central and South America have the highest species richness, followed by Asia (28 species) and Africa (27 species). Europe and North America harbor 16 species each and Australia 11. This group includes the well-known mallard (A. platyrhynchos) and the American black duck (A. rubripes). Five species and 2 subspecies are limited entirely to islands, such as New Zealand, Madagascar, and Hawaii. The Merginae are a group of the north temperate and Arctic regions. Most species can be found in North America. The Oxyurinae are distributed on all continents, but are more prevalent in South America, Africa, and Australia.

Habitat

The Anatidae can be found anywhere as long as some wetland or body of water is present. For instance, the marbled teal (Marmaronetta angustirostris) lives in arid regions of the Mediterranean, the oldsquaw in the high Arctic tundra, and the Brazilian teal (Amazonetta brasiliensis) in the lush rain-forests of South America. Five species require fast flowing streams and two hardly depend on aquatic habitats at all. The Cape Barren goose (Cereopsis novaehollandiae) enters the water only while molting its wing feathers or rearing young and the Hawaiian goose inhabits the lava fields of volcanoes. In contrast, the scoters (Melanitta) rarely go ashore except during reproduction. Several species can be found at high elevation. A good example is the bar-headed goose (Anser indicus) which breeds on the highland plateaus of the central Asia, between 13,100 and 16,400 ft (4,000–5,000 m).

Behavior

Almost half of the species (47.6%) in this family are either completely or partially migratory. Of the remaining species the vast majority wander over wide areas in response to changing water levels. During migration, waterfowl may fly at high altitudes, as high as 32,800 ft (10,000 m) in some geese.

One of the most notable aspects of waterfowl behavior are the highly ritualized displays. The specific functions of displays are to aid in family group cohesion, convey information about the reproductive status, establish pair bonds, defend a mate or territory, and prevent hybridization. The displays may have originated from common behavioral patterns as they bear a remarkable resemblance to movements used in plumage maintenance (e.g. preening, bathing, and shaking), feeding, and locomotion.

Typical for the Anserinae is the so-called "triumph ceremony," which is used to establish dominance status in wintering flocks as well as to advertise territories in the breeding season.

The Dendrocygninae are gregarious and to large degree nocturnal or crepuscular. Auditory signals are therefore very important. Within the Tadorninae, the highly aquatic steamerducks (Tachyeres) stretch their necks and cock their tails as the most conspicuous means to signal from the water surface. Paired females in Tadorna (also in Aythya) perform a display called "inciting." It shows an intruding male that she already has a partner and stimulates her mate to attack the intruder.

The voices of the Anatidae vary from whistling sounds in whistling-ducks and sea ducks, to a variety of typical "quack" sounds in dabbling ducks and deep honks in swans. Most species posses a bulla, a more or less ossified enlargement at the union between that trachea and the bronchi, that acts as a resonating body.

The Anatinae are a very diverse group with a variety of habitat-specific displays. The torrent duck (Merganetta

armatta) is especially interesting because it does not share its display repertoire with any other species of ducks. For instance, it uses its legs in hostile displays in which it also reveals painful wing spurs.

The Merginae have complex signaling systems as courtship occurs mainly on the water. Vocal repertoires are diverse and many species use courting flights and/or underwater pursuits. The precopulatory behaviors in common eiders (Somateria mollisima) are extremely, and puzzlingly, complex.

The Oxyurinae have many distinct behavioral features not shared with any other group. Birds may be seen contorting their necks and tails into bizarre postures.

Feeding ecology and diet

Although most swans, geese, and ducks require wetlands or other water-bodies for their survival, not all species forage in the water. The subfamilies Anseranatinae, Dendrocygninae, Anserinae, and some Tadorninae (especially Chloephaga) feed mostly on land on a largely vegetarian diet. Tachyeres steamerducks eat almost exclusively on aquatic invertebrates. The Anatinae are largely omnivorous and the Merganinae are largely piscivorous and insectivorous. The Oxyurinae, complement a diet based on aquatic invertebrates with seeds and green parts of aquatic plants.

The methods used in feeding are as varied as the diets. Vegetarians often graze or browse on land. Most species that feed in the water dabble, dip their heads into the water, or upend by immersing half of their body head down. The more aquatic species mostly forage by diving. The duration of the dives is usually 60–70 seconds, but may be as long as 2 min in some scoters (Melanitta).

Reproductive biology

Most species of Anatidae are monogamous. The Anserinae, Dendrocygninae, and Tadorninae may stay paired for several seasons, mute swans even for life. With the exception of some promiscuous stifftails, most ducks are seasonally monogamous. Pair bonds often last only halfway through the breeding season until midincubation or hatching of the young. The Anseranatinae are unusual among the waterfowl in that they form polygamous "trios."

Breeding in the temperate regions usually begins in the spring. In those species that are not perennially monogamous, pair formation is most often achieved before the breeding season. In other species, such as the ruddy duck (Oxyura jamaicensis), pair formation takes place on the breeding grounds. In tropical latitudes the beginning of the breeding season is variable, depending to large degree on water levels.

The nests are made on the ground with surrounding vegetation or in cavities. Most species also line their nests with down and feathers. The magpie goose builds its nest on a mound of floating vegetation. Most Dendrocygninae, Anserinae, and Anatinae make ground nests. The Tadorninae has both ground and cavity nesters. The Merginae nest on the ground, oftentimes in nothing more than a small depression. The Oxyurinae build their nests of vegetable matter on the ground although some stiff-tails reuse nests of other species.

On average, clutch size is of 4 to 16 eggs. Should a clutch fail, relaying occurs after 4–20 days. Incubation lasts between 22 and 40 days. Sexual maturity is usually attained after the first to third year. The eggs are large, and the young hatch completely covered with down and are able to swim and dive within a few hours.

An interesting aspect of anatid reproductive behavior is that many species parasitize the nests of other birds, most often of the same species. Up to 30 eggs may accumulate in socalled "dump nests." The black-headed duck (Heteronetta atricapilla) is entirely parasitic.

Male parental care (incubation and protection of young) is uncommon in the Anatidae. It can be found mostly in species that are perennially monogamous and in several tropical Anatinae. In the latter, an unpredictable environment and breeding season force the drake to secure a mate before environmental conditions are favorable. The male magpie goose and the comb duck even feed the young.

Conservation status

Five species have already become extinct due to over-hunting in historic times and at least 14 more in prehistory. The latter are almost all island species that disappeared as people colonized the Pacific islands and New Zealand. Thirty-three species (22%) and 5 subspecies are under some category of threat as defined by the IUCN. Most of these species come from Asia or islands, such as Hawaii, New Zealand, and Madagascar. Of the four species listed as Critically Endangered, three, the crested shelduck (Tadorna cristata), the pink-headed duck (Rhodonessa caryophyllacea),

and the Madagascar pochard (Aythya innotata) may already have become Extinct. Five species and two subspecies are Endangered. The Vulnerable list includes 11 species and two subspecies. An additional seven species are considered Near Threatened.

The greatest threat comes from overhunting and wetland drainage. Large quantities of waterfowl are still hunted during migration, especially in Siberia. In Asia, a largely poor rural population also puts pressure on waterfowl by subsistence hunting. Wetland drainage results in a loss of suitable breeding habitat. The destruction of habitat surrounding the main breeding areas can also be detrimental. The river specialists, for instance, suffer from increased siltation caused by deforestation.

Significance to humans

The Anatidae have always had a close relationship with humans. At least four species have been domesticated: the greylag goose, swan goose (Anser cygnoides), muscovy duck, and mallard (Anas platyrhynchos). More than 23 variants of mallard are known. The mute swan and Canada goose (Branta canadensis) are kept in semi-liberty.

Waterfowl have been hunted ever since Homo sapiens walked the earth. Considered a delicacy by almost all cultures, at the end of the twentieth century their hunting and observation has also become a lucrative business with significant economic impact. In America, outdoor stores sell millions of dollars worth of hunting gear and many states also derive benefit through hunting licenses. More importantly, they are an important element in the maintenance of wetland ecosystems.

Ducks, geese, and swans figure prominently in myths and stories. For example, in Greek mythology Zeus took on the form of a swan in order to conquer Leda. In the Germanic Lohengrin saga, the knight is pulled over a lake by swans, which symbolize purity and love.

In science, observations on waterfowl displays have advanced our knowledge on animal behavior in general. Waterfowl still promise to be great model species for studies on sexual selection, the origin of mating systems, and the mechanistic basis of behavior.

Species accounts

List of Species

Magpie goose

Anseranas semipalmata

subfamily

Anseranatinae

taxonomy

Anas semipalmata Latham, 1798, Hawkesbury River, New South Wales, Australia. Monotypic.

other common names

English: Pied goose; Semipalmated goose; French: Canaroie semipalmé; German: Spaltfußgans; Spanish: Ganso Urraco.

physical characteristics

27.6–35.4 in (70–90 cm); female 4.4 lb (2.0 kg); male 6.2 lb (2.8 kg); webs on the toes reduced; hind toe very long.

distribution

Southern New Guinea and Queensland, Australia; reintroduced in Victoria, southeastern Australia.

habitat

Swamps and grasslands in riverine floodplains.

behavior

Often bigamous. Parental care extensive. Gregarious.

feeding ecology and diet

Feeds on grasses and seeds using its feet to bend down taller plants. Also digs out roots and bulbs with its hooked bill.

reproductive biology

Often bigamous, with one male paired with two females. One or both females lay 1-16 eggs in same nest, Feb.–Apr. in north, Aug.–Sept. in south. The nest is a mound of floating vegetation. Incubation 23–25 days; fledging c. 11 weeks; sexual maturity after two years in females and 3–4 years in males.

conservation status

Size of populations increasing. Generally common in its habitat. Protected from hunting except during open season in Northern Territory, Australia.

significance to humans

Hunted traditionally by aboriginies. Considered a pest by rice growers.

White-faced whistling duck

Dendrocygna viduata

subfamily

Dendrocygninae

taxonomy

Anas viduata Linnaeus, 1766, Cartagena, Colombia. Monotypic.

other common names

English: White-faced tree duck; French: Dendrocygne veuf; German: Witwenpfeifgans; Spanish: Suirirí Cariblanco.

physical characteristics

15–19 in (38–48 cm); 1.1–1.8 lb (502–820 g). Brown and gray feathers with dark neck and eponymous white face.

distribution

Throughout tropical America from Costa Rica south through northern and eastern Colombia and Guyana in east; in south

from eastern Bolivia east to Uruguay; Trinidad. In Africa south of the Sahara to Namibia and Natal; Madagascar; Comoro Islands.

habitat

Freshwater marshes, grassy lagoons, and flooded fields.

behavior

Not territorial. Move regionally as a response to varying water levels.

feeding ecology and diet

Forages mainly at night by diving; also wades and dabbles near surface. Feeds on grasses, seeds, rice, and invertebrates.

reproductive biology

Perennially monogamous. Breeds during rainy season. Well-concealed nests made on the ground. Lay 4–13 eggs; incubation 26–28 days; fledging c. 8 weeks.

conservation status

Not threatened. Common throughout range.

significance to humans

None known.

Mute swan

Cygnus olor

subfamily

Anserinae

taxonomy

Anas olor Gmelin, 1789, "Russia, Sibiria, Persico etiam littore maris Caspii." Monotypic.

other common names

French: Cygne tuberculé; German: Höckerschwan; Spanish: Cisne Vulgar.

physical characteristics

49–63 in (125–160 cm); 14.6–33 lb (6.6–15.0 kg). Characteristic knob on bill.

distribution

Central and northern Europe, locally in Russia and Siberia, patchily from Turkey to eastern China. Winters in northern Africa, Black Sea, northwestern India, and Korea. Populations anywhere else are introduced.

habitat

Freshwater marshes, lagoons, and rivers; artificial lakes and canals.

behavior

Territorial. The 11.12 acres (4.5 ha) large territories defended very aggressively, even by killing other birds. Clap feet on water and perform rotation displays to advertise their territories. Migratory.

feeding ecology and diet

Feeds mostly on aquatic vegetation, seeds, grasses, small amphibians, and invertebrates. Dabbles and rarely dives.

reproductive biology

Perennially monogamous. Breeds in spring. Nests are large platforms of vegetation built on floating mats or reeds. Lay

5–7 eggs. Incubation 35–36 days; fledging 120–150 days; become sexually mature at the earliest during the third year.

conservation status

Range expanding and abundances increasing.

significance to humans

Symbolizes purity, love, and elegance in many cultures making it the stuff of myths. Common in parks.

Canada goose

Branta canadensis

subfamily

Anserinae

taxonomy

Anas Canadensis Linnaeus, 1758, City of Quebec, Canada. Sub-species considered by some as full species.

other common names

French: Bernache du Canada; German: Kanadagans; Spanish: Barnacla Canadiense.

physical characteristics

21.7–43.3 in (55–110 cm); 4.5–14.4 lb (2.06–6.52 kg). Large long-necked goose with dark solid-colored neck and mottled plumage.

distribution

B. c. leucopareia: Aleutian Islands; winters in California. B. c. minima: west coast of Alaska; winters in California. B. c. taverneri: Alaska to western Northwest Territory; winters in Washington south to northern Mexico. B. c. occidentalis: southwestern Alaska; winters from Prince William Sound south to northern California. B. c. fulva: coastal southern Alaska and western British Columbia. B. c. parvipes: north central Canada; winters from California south to Louisiana and northern Mexico. B. c. moffitti: British Columbia east to Manitoba and in south from northern California to eastern Colorado; winters in southern part of its range and northern Mexico. B. c. maxima: Alberta to Manitoba. B. c. hutchensii: arctic tundra of Canada; winters in New Mexico, Texas, and northeastern Mexico. B. c. interior: central and eastern Canada; winters from Wisconsin east to New York, and south to Gulf and Atlantic coasts. B. c. canadensis: northeastern Canada; winters along eastern coastal provinces of Canada south to North Carolina. Introduced into United Kingdom, northwestern Europe, and New Zealand.

habitat

Mostly open habitats such as tundra, semi-desert, wooded areas, and agricultural lands.

behavior

Territorial to colonial. Migratory.

feeding ecology and diet

Diet mostly vegetarian. Grazes on land and submerges head when on water.

reproductive biology

Perennially monogamous with mate guarding. Breeds in spring. Usually lay 4–7 eggs in shallow ground nest; incubation 24–30 days; fledging 40–86 days; Sexually mature at 2–3 years.

conservation status

Not threatened, though some populations have declined due to over-hunting and habitat alteration.

significance to humans

Hunted for game.

Cape Barren goose

Cereopsis novaehollandiae

subfamily

Anserinae

taxonomy

Cereopsis n. hollandiae Latham, 1801, New South Wales = islands of Bass Strait. Monotypic.

other common names

English: Cereopsis goose; French: Céréopse cendrée; German: Hühnergans; Spanish: Ganso Cenizo.

physical characteristics

29.5–39.4 in (75–100 cm); 7–14 lb (3.17–6.80 kg). Pale gray, with distinctive dark spots on wings.

distribution

Islands off southern Australia from Recherche Archipelago to Tasmania.

habitat

Scrub and grassy areas near coast; edges of lakes and lagoons.

behavior

Territorial or colonial during the breeding season, but disperse after breeding season. Perform triumph ceremonies.

feeding ecology and diet

Feeds on grasses, seeds of grasses, sedges, and leaves by grazing.

reproductive biology

Perennially monogamous. Breeds in southern winter May–Jun. Lays 3–6 eggs into shallow ground nest; incubation c. 34–37 days; fledging 70–76 days.

conservation status

Not threatened. Populations stabile due to favorable conditions on agricultural lands and a stop of intensive hunting.

significance to humans

Limited hunting allowed in Tasmania.

Ruddy shelduck

Tadorna ferruginea

subfamily

Tadorninae

taxonomy

Anas ferruginea Pallas, 1789, no locality = Tartary. Monotypic.

other common names

English: Brahminy duck; French: Tadorne casarca; German: Rostgans; Spanish: Taro Canelo.

physical characteristics

24.8–26 in (63–66 cm); 2.0–3.6 lb (925–1,640 g). Golden head, ruddy brown body, and iridescent green secondary feathers.

distribution

Patchy from southern Spain and northwestern Africa east to Mongolia; winters south of breeding range in Africa, Arabia, and East Asia.

habitat

Brackish lakes, lagoons, and wetlands in mostly open landscapes.

behavior

Territorial during breeding season. Asian populations are mostly migratory.

feeding ecology and diet

Feeds on plants and invertebrates on land and water by grazing, dabbling and upending.

reproductive biology

Seasonally monogamous, but pair bonds may last several seasons. Breeding begins in Mar. or Apr. Nests in cavities. Lays usually 8–9 eggs; incubation c. 28–29 days; fledging c. 55 days; becomes sexually mature at 2 years.

conservation status

Has declined (now recuperating?) in western part of the range due to hunting and wetland drainage. Asian populations appear healthy.

significance to humans

Hunted for food.

Magellanic steamerduck

Tachyeres pteneres

subfamily

Tadiorninae

taxonomy

Anas pteneres Foster, 1844, Tierra del Fuego. Monotypic.

other common names

English: Magellanic flightless steamerduck; French: Brassemer cendré; German: Magellan-Dampfschiffente; Spanish: Patovapor de Magellanes.

physical characteristics

29.1–33.1 in (74–84 cm); 8.0–13.6 lb (3.63–6.18 kg); small wings render it almost flightless.

distribution

Coastal Chile from Chiloé Island south to Cape Horn, and coastal Argentina from Chubut south to Tierra del Fuego and Staten Island.

habitat

Rocky shores and sheltered bays, often several miles from coast.

behavior

Highly territorial and very aggressive. Both males and females defend territory. Perform triumph ceremonies. Moves over water by flapping wings like a steamer boat. Sedentary.

feeding ecology and diet

Feeds by diving in shallow kelp beds for marine mollusks and crustaceans.

reproductive biology

Perennially monogamous. Breeding starts Sept. or Oct.. Lay 5–8 eggs into well hidden nests; incubation c. 30–40 days.

conservation status

Common in limited range.

significance to humans

None known.

Comb duck

Sarkidiornis melanotos

subfamily

Anatinae

taxonomy

Anser melanotos Pennant, 1769, Ceylon. Two subspecies.

other common names

English: Knob-billed duck, black-backed goose; French: Canard-à-bosse bronzé; German: Glanzente; Spanish: Pato Crestudo.

physical characteristics

22.1–29.9 in (56–76 cm); 2.7–5.8 lb (1.23–2.61 kg); males have a prominent black fleshy crest on upper bill.

distribution

S. m. melanotos: Africa south of Sahara and Madagascar; from Pakistan through tropical India to southern China. S. m. sylvicola: eastern Panama, western Ecuador, eastern Colombia east through Guyana and south to northern Argentina and Uruguay; occasionally Trinidad.

habitat

Open swamps, rivers, and lakes with sparse trees.

behavior

Very sociable. Males defend 17.3 acres (7 ha) large territories, threatening intruders with wing flap display. Female/female aggression common while searching for nest cavities.

feeding ecology and diet

Vegetarian, but also feeds on some invertebrates. Grazes on land; swims, dabbles, and wades in shallow water.

reproductive biology

Seasonally monogamous, but sometimes polygynous. Forced copulations are common. Breeding season depends very much on the local rainy season. Nests in tree cavities or occasionally on ground. Lays 6–20 eggs; incubation c. 28–30 days; fledgingc. 10 weeks.

conservation status

Listed on Appendix II of CITES. South American subspecies is uncommon and threatened by deforestation, hunting, and poisoning by rice farmers. African and Asian populations are not threatened.

significance to humans

Considered a pest by rice farmers. Hunted for food.

African pygmy goose

Nettapus auritus

subfamily

Anatinae

taxonomy

Anas aurita Boddaert, 1783, Madagascar. Monotypic.

other common names

English: Dwarf goose, pygmy goose; French: Anserelle naine; German: Afrikanische Zwergente; Spanish: Gansito Africano.

physical characteristics

11.8–13.0 in (30–33 cm); 0.57–0.63 lb (260–285 g). Iridescent green back with ruddy flanks and white underparts.

distribution

South of Sahara except southwestern Africa; islands of Pemba, Zanzibar, Mafia, and Madagascar.

habitat

Shallow wetlands and slow flowing rivers with abundant floating aquatic vegetation, preferrably water lilies.

behavior

Territorial and sedentary, but moves in response to habitat changes.

feeding ecology and diet

Feeds on insects and quatic plants, especially seeds of water lillies, while swimming. Also dives for small fish and aquatic insects.

reproductive biology

Seasonally monogamous in captivity and in the wild. Nests in tree cavities. Lays 6–12 eggs; incubation c. 23–24 days; sexually mature probably at 1 year.

conservation status

Not threatened. Locally common to abundant. Listed on Appendix III of CITES for Ghana.

significance to humans

Hunted for food.

Mandarin duck

Aix galericulata

subfamily

Anatinae

taxonomy

Anas galericulata Linnaeus, 1758, China; monotypic.

other common names

French: Canard mandarin; German: Mandarinente; Spanish: Pato Mandarín.

physical characteristics

16.1–20.1 in (41–51 cm); 0.98–1.10 lb (444–500 g). Multicolored upperparts of gray, green, black, and ruddy brown. White underparts.

distribution

Eastern Siberia and eastern Chinasouth to South Korea and Japan; winters in southeastern China below 40° north and Taiwan.

habitat

Fast flowing rocky streams and wooded ponds.

behavior

Not known if territorial. Migratory.

feeding ecology and diet

Feeds on grains, seeds, and acorns as well as land snails, little fish, and insects. Forages by dabbling, dipping head into the water, and upending.

reproductive biology

Seasonally to perennially monogamous; some forced copulations may occur. Breeding begins in Apr. Nests in tree holes up to 30 ft (10 m) high. Lays 9–12 eggs; incubation 28–30 days; fledging c. 40–45 days. Sexually mature at 1 year.

conservation status

Not threatened, but of special concern as populations have declined over several decades during the twentieth century.

significance to humans

Bred by aviculturalists. In China and Japan symbolizes happiness and marital fidelity. Not hunted for food because distasteful.

Torrent duck

Merganetta armata

subfamily

Anatinae

taxonomy

Merganetta armata Gould, 1842, Andes of Chile. Six subspecies.

other common names

French: Merganette des torrents; German: Sturzbachente; Spanish: Pato de torrente.

physical characteristics

16.9–18.1 in (43–46 cm); 0.69–0.97 lb (315–440 g); slender bodied.

distribution

M. a. colombiana: Andes of western Venezuela south to southern Ecuador. M. a. leucogenis: Andes of southern Ecuador south to northwest Argentina. Merganetta a. armata: Andes of Mendoza, Argentina, and Atacama, Chile, south to Tierra del Fuego. Found between 984 and 15,100 ft (300–4,600 m), in south down to sea level.

habitat

Fast-flowing, rocky mountain streams with clear water in páramo grasslands and humid montane forest.

behavior

Very territorial and aggressive year round.

feeding ecology and diet

Feeds on aquatic invertebrates and possibly fish. Forages by diving, dipping head into water, and upending; searches crevices among rocks and boulders.

reproductive biology

Perennially monogamous. May mate for life. Grassy nest lined with down can be found in cavities, among rocks, or in dense vegetation. Breeding season depends on locality. Lays 3–4 eggs; incubation c. 43–44 days.

conservation status

M. a. colombiana and M. a. leucogenis appear to be declining and may soon be considered Near Threatened. Main causes for the decline are deforestation, river siltation, hunting, and mining.

significance to humans

Hunted for food.

Salvadori's teal

Anas waigiuensis

subfamily

Anatinae

taxonomy

Salvadorina waigiuensis Rothschild and Hartert, 1894, Waigeo. Monotypic.

other common names

English: Salvadori's duck; French: Canard de Salvadori; German: Salvadoriente; Spanish: Anade Papúa.

physical characteristics

15.0–16.9 in (38–43 cm); 0.88–1.2 lb (400–550 g). Dark head, barred wings, and stippled feathers.

distribution

Mountains of New Guinea.

habitat

Fast flowing mountain streams and brooks as well as slower flowing small rivers and small lakes; from 1,640–11,800 ft (500–3,600 m) elevation.

behavior

Territorial year round.

feeding ecology and diet

Feeds mostly on aquatic invertebrates and possibly tadpoles and small fish.

reproductive biology

Perennially monogamous. Possibly produces two broods a year. Lays 3–4 eggs; incubation longer than 28 days.

conservation status

Not threatened. Locally common. May become threatened due to increased hunting, river pollution, predation by introduced mammals, and competition with introduced predatory fish.

significance to humans

Hunted for food.

American wigeon

Anas americana

subfamily

Anatinae

taxonomy

Anas americana Gmelin, 1789, Lousinana and New York. Monotypic.

other common names

English: Baldpate; French: Canard d'Amérique; German: Nordamerikanische Pfeifente; Spanish: Silbón Americano.

physical characteristics

17.7–22.1 in (45–56 cm); 1.5–1.7 lb (680–770 g). Male has dark green band along side of head.

distribution

Western and Central North America; some populations breed from New Brunswick south to Massachusets. Winter from Alaska south to Central America, Gulf and Atlantic coasts.

habitat

Shallow lakes and open wetlands surrounded by meadows or agricultural lands; during winter mostly in coastal wetlands.

behavior

Territorial during the early breeding season. Paired males swim 'in tandem' with lone intruding males. Migratory.

feeding ecology and diet

Vegetarian, feeds by walking, wading, or swimming in shallow water.

reproductive biology

Seasonally monogamous until midincubation. Breeding begins Apr.–May. Lays 4–8 eggs into a concealed shallow depression; incubation 23–25 days; fledging c. 37–48 days. Becomes sexually mature at 1–2; years.

conservation status

Not threatened. Locally abundant. Critical habitats protected.

significance to humans

Hunted for sport and food.

Brown teal

Anas aucklandica

subfamily

Anatinae

taxonomy

Nesonetta aucklandica G. R. Gray, 1844, Auckland Islands; the three subspecies may deserve species status.

other common names

English: Brown duck, New Zealand teal, Pateke; French: Sarcelle brune; German: Auklandente; Spanish: Cerceta Maorí.

physical characteristics

14.2–18.9 in (36–48 cm); 0.8–1.5 lb (375–700 g); A. a. aucklandica and A. a. nesiotis are flightless.

distribution

New Zealand and nearby islands. A. a. aucklandica: Auckland Islands. A. a. chlorotis: patchily distributed on North Island and southwestern South Island. A. a. nesiotis: Dent Island to the northwest of Campbell Island; 12 individuals have been released on Codfish Island in 1999.

habitat

Sheltered coastlines with kelp beds, inland wetlands with some tree cover.

behavior

Male participates in brood rearing. Very territorial during the early breeding season. Males patrol territories using aggressive displays and chest-to-chest fighting. Often nocturnal.

feeding ecology and diet

Feeds by probing, dabbling, upending, and diving. Searches for food in kelp beds, washed-up algae on beaches, marshes, ponds, and slow flowing waters. Diet consists invertebrates, roots, and tips of shoots.

reproductive biology

Seasonally monogamous. Nest is well hidden in thick vegetation. A. a. chlorotis breeds mostly from Jun. to Oct. and A. a. aucklandica begins breeding season in Dec.–Jan.

Probably lays 4–8 eggs; incubation c. 29–30 days; fledging c. 50–55 days.

conservation status

A. a. aucklandica considered Vulnerable and A. a. chlorotis Endangered. Only about 25 pairs remain of A. a. nesotis which is considered Critically Endangered. The species appears to be declining due to introduced predators, habitat destruction, and hunting. Listed on Appendix I of CITES.

significance to humans

Sometimes hunted.

Mallard

Anas platyrhynchos

subfamily

Anatinae

taxonomy

Anas platyrhynchus Linnaeus, 1758, Europe. Seven subspecies.

other common names

English: Greenhead, koloa; French: Canard colvert; German: Stockente; Spanish: Anade Azulón.

physical characteristics

19.7–25.6 in (50–65 cm); 1.7–3.5 lb (750–1,580 g). Green head, brown chest, blue speculum.

distribution

A. p. platyrhynchus: widespread throughout the nearctic, in palearctic from Iceland to Kamchatka and south to the Mediterrean; winters on most of Pacific coast from the Aleutians

to California, southern half of the United States, northeastern Mexico, the West Indies, northern Africa, and from Iraq west to southeastern China. A. p. conboschas: coasts of southern Greenland. A. p. fulvigula: coastal Alabama west to Florida peninsula. A. p. maculosa: Gulf coast from Mississippi south to central Tamaulipas, Mexico; winters south to Veracruz. A. p. diazi: southeastern Arizona to western Texas and south to Mexico. A. p. wyvilliana: Kauai, Oahu, and Hawaii, Hawaiian Islands. A. p. laysanensis: Laysan Island, Hawaiian Islands. Populations elsewhere are introduced.

habitat

Shallow and calm waters of all types of natural or artificial wetlands and saltwater and brackish water. Prefers some vegetative cover.

behavior

Territorial to midincubation. Males then abandon their mates and territory. The c. 39.54–274.29 acres (16–111 ha) large, overlapping territories are defended aggressively. Forced copulations occur. Typical behaviors are the grunt-whistle and head-up-tail-up displays used in courtship. Migratory.

feeding ecology and diet

Feeds on water by dabbling, head-dipping, upending, and rarely diving, and on land forages by grazing and probing. Omnivorous diet includes terrestrial and aquatic invertebrates, fish, amphibians, and various plant parts.

reproductive biology

Seasonally monogamous. Breeding begins Feb.–Jun., depending on locality. The nest is made in a cavity or the ground. Generally lays 9–13 eggs; incubation c. 27–28 days; fledging 50–60 days. Becomes sexually mature at 1 year.

conservation status

Common. Only Hawaiian subspecies are rare. A. p. laysanensis considered Vulnerable and listed on Appendix I of CITES. A. p. wyvilliana considered Critically Endangered. The other subspecies are common. A. p. diazi may be threatened by hybridization with southward spreading A. p. platyrhynchus.

significance to humans

Hunted for sport.

Northern shoveler

Anas clypeata

subfamily

Anatinae

taxonomy

Anas clypeata Linnaeus, 1758, coasts of Europe. Monotypic.

other common names

English: Shoveler; French: Canard souchet; German: Löffelente; Spanish: Cuchara Común.

physical characteristics

16.9–22.1 in (43–56 cm); 0.9–2.4 lb (410–1,000 g). Green head, white breast, ruddy underparts.

distribution

Throughout most of the Nearctic and Palearctic. Winters in southern United States south to Colombia, in Mediterranean east to southeastern Asia and south to tropical Africa.

habitat

Open, shallow freshwater wetlands and, in winter, brackish waters and tidal mudflats.

behavior

Territorial during early breeding season. Males aggressive; use wing noises to advertise their presence on a territory and chase intruders. Migratory.

feeding ecology and diet

Omnivorous diet consisting of small aquatic invertebrates, seeds, and vegetative parts of plants. Feed by dabbling.

reproductive biology

Seasonally monogamous. Pair bonds last through brood rearing. Breeding season begins in Apr–May. Lays 9–11 eggs in a depression on the ground; incubation c. 22–23 days; fledging 40–45 days; becomes sexually mature at 1 year.

conservation status

Not threatened. Locally common. Listed on Appendix III of CITES for Ghana.

significance to humans

Hunted for food and sport.

Marbled teal

Marmaronetta angustirostris

subfamily

Anatinae

taxonomy

Anas angustirostris Ménétriés, 1832, Lenkoran. Monotypic.

other common names

English: Marbled duck; French: Sarcelle marbrée; German: Marmelente; Spanish: Cerceta Pardilla.

physical characteristics

15.4–18.9 in (39–48 cm); 1.0–1.3 lb (450–590 g). Plumage mainly grayish brown with white marbling.

distribution

From southern Spain and northwestern Africa east to Pakistan; winters south of breeding range to the northern Sahara and east to northwestern India.

habitat

Heavily vegetated brackish marshes within arid regions.

behavior

Not territorial, but male guards female until she finishes laying eggs. Migratory.

feeding ecology and diet

Feeds on plant parts and aquatic invertebrates by dabbling, upending, diving, mud-filtering, and wading on shore.

reproductive biology

Seasonally monogamous. Breeding begins in Apr.–Jun., and May–Jul. in northern Africa. Lays 7–14 eggs into a small concealed depression on ground; incubation 25–27 days; becomes sexually mature at 1 year.

conservation status

Populations are declining due to hunting and wetland drainage. Considered Vulnerable.

significance to humans

Hunted for food.

Madagascar pochard

Aythya innotata

subfamily

Anatinae

taxonomy

Nyroca innotata Salvadori, 1894, Madagascar. Monotypic.

other common names

English: Madagascan white-eye; French: Fuligule de Madagascar; German: Madagascarmoorente; Spanish: Porrón Malgache.

physical characteristics

17.7–22.1 in (45–56 cm). Brown duck with white belly.

distribution

Occurs only in and around Lake Aloatra in eastern Madagascar.

habitat

Freshwater wetlands with a mixture of open water and vegetation islands.

behavior

Not known.

feeding ecology and diet

Mostly dives for aquatic invertebrates and seeds of aquatic plants.

reproductive biology

Probably monogamous. Nesting has been observed Mar.–Apr. Hidden nests are slightly raised on a bank or a clump of vegetation.

conservation status

Considered Critically Endangered, but possibly extinct. Last seen in 1991. Declined due to habitat conversion and excessive hunting.

significance to humans

Hunted for food.

King eider

Somateria spectabilis

subfamily

Merginae

taxonomy

Anas spectabilis Linneaus, 1758, Canada, Sweden. Monotypic.

other common names

French: Eider à tête grise; German: Prachteiderente; Spanish: Eider Real.

physical characteristics

16.9–24.8 in (43–63 cm); 3.3–4.4 lb (1.50–2.01 kg). Male has colorful blue, yellow, and white head.

distribution

Coasts of the Arctic. Winters off the coast of Iceland, Norway, and Kuril and Aleutian Islands in the Old World, and as far south as California and Long Island in the New world.

habitat

Open marine waters. Breeds on nearby land in Arctic freshwater wetlands.

behavior

Sometimes semi-colonial with the male guarding his mate. Migratory.

feeding ecology and diet

Feeds mostly on marine invertebrates. Dives in deep water and upends and head-dips in shallow water. Also eats the green parts of tundra vegetation.

reproductive biology

Seasonally monogamous until midincubation. Some forced copulations occur. Breeding begins in Jun. Lays 4–5 eggs into a deep depression on the ground with little nesting material; incubation 22–24 days; becomes sexually mature at 3 years.

conservation status

Not threatened. Common throughout its range. Has disappeared from Kuril Island. Intense hunting pressure during migration and possible oilspills during the nonbreeding season may pose future threats.

significance to humans

Hunted for food and game.

Harlequin duck

Histrionicus histrionicus

subfamily

Merginae

taxonomy

Anas histrionicus Linnaeus, 1758, America = Newfoundland ex Edwards. Monotypic.

other common names

English: Harlequin; French: Arlequin plongeur; German: Kragenente; Spanish: Pato Arlequín.

physical characteristics

15.0–20.1 in (38–51 cm); 1.2–1.5 lb (540–680 g). Distinctive white markings on head, chest, and back.

distribution

Eastern Siberia from Lake Baikal north to about 68° and east to central western Alaska and Yukon. South in North America to California and east to southern Baffin Island and Quebec. Greenland, and Iceland. Winters along coasts of Kamchatka, Bearing Sea islands, Japan, Korea, China, California, and from southern Labrador south to Long Island.

habitat

Fast flowing rocky rivers during the breeding season and rocky coastlines during the nonbreeding season.

behavior

Loosely territorial and aggressive. Males guard their mate. Return to the same breeding area each year. Migratory.

feeding ecology and diet

Has mostly an animal diet of invertebrates and some fish. Mostly dives for food, but also dabbles, up-ends, and dips its head in shallow water.

reproductive biology

Seasonally monogamous until midincubation. Same birds may re-pair in the following season. Breeding begins May–Jun. The nest is well hidden on the ground. Commonly lays 5–7 eggs; incubation 27–29 days; fledging c. 60–70 days; becomes sexually mature at 2 years.

conservation status

Not threatened. Locally common with stable populations.

significance to humans

None known.

Oldsquaw

Clangula hyemalis

subfamily

Merginae

taxonomy

Anas hyemalis Linnaeus, 1758, Arctic Europe and America; monotypic.

other common names

English: Long-tailed duck; French: Harelde borréale; German: Eisente; Spanish: Pato Havelda.

physical characteristics

15.0–22.8 in (38–58 cm); 1.4–1.8 lb (650–800 g). Plumage brighter in winter. Characteristic long streamers.

distribution

Coasts of the high Arctic. Winters south of breeding area along coastlines of Bearing Sea Islands, southern Alaska to California, Great Lakes, Atlantic coast from southern Labradador to the Carolinas, the British Isles, Northern and Baltic Seas, Caspian Sea, various lakes in Turkistan, Japan, Korea, and northeastern China.

habitat

Breeds in wetlands of tundra and Arctic coasts. Winters in open sea and large deep freshwater lakes.

behavior

Territorial until hatching of young. Male defends a 1.24 acres (0.5 ha) small territory on which the female forages, but does not nest. Intruders are threatened with various displays and vocalizations before being chased in flights. Migratory.

feeding ecology and diet

Feeds by diving on marine invertebrates and fish. Rarely consumes plant matter.

reproductive biology

Seasonally monogamous. Breeding begins May–Jun. Lays 6–9 eggs into a small depression; incubation 24–29 days; fledging 35–40 days; becomes sexually mature at 2 years.

conservation status

Not threatened. Common to abundant throughout its range. Threats include excessive hunting and oil spills which may kill thousands of birds aggregating in large rafts.

significance to humans

Intensively hunted.

Brazilian merganser

Mergus octosetaceus

subfamily

Merginae

taxonomy

Mergus octosetaceus Vieillot, 1817, Brazil. Monotypic.

other common names

French: Harle huppard; German: Dunkelsäger; Spanish: Serreta Brasileña.

physical characteristics

19.3–22.1 in (49–56 cm). Iridescent green crest and head on stippled gray-brown body.

distribution

Southeastern Brazil, eastern Paraguay, and northeastern Argentina

habitat

Fast flowing rivers and streams surrounded by tropical forest.

behavior

Territorial with pairs defending stretches of river.

feeding ecology and diet

Feeds mostly on fish and some invertebrates by diving.

reproductive biology

Apparently seasonally monogamous. Breeds during rainy season (beginning Jun.). Nest in tree cavities.

conservation status

Considered Critically Endangered. Only few populations are known. Major threats include habitat destruction and hunting.

significance to humans

Hunted for food.

Black-headed duck

Heteronetta atricapilla

subfamily

Oxyurinae

taxonomy

Anas atricapilla Merrem, 1841, Buenos Aires. Monotypic.

other common names

French: Hétéronette à tête noire; German: Kukkucksente; Spanish: Pato Rinconero.

physical characteristics

13.8–15.8 in (35–40 cm); 1.1–1.3 lb (513–565 g). Black head and upperparts, mottled brown underparts.

distribution

Santiago, Chile, in west, to Paraguay and Buenos Aires province, Argentina, in east.

habitat

Freshwater wetlands with abundant emergent vegetation in open or sparsely vegetated regions.

behavior

Not known.

feeding ecology and diet

Feeds on seeds, plants, and some aquatic invertebrates by diving, dabbling, head-dipping, upending, and mud-filtering.

reproductive biology

Probably seasonally monogamous for only short periods of time. Breeding mostly between Sept. and Dec. Only completely parasitic

anatid. Female lays on average 2 eggs in the nests of other waterfowl, especially coots (Fulica) and rosy-billed porchard.

conservation status

Common throughout its range, but may be threatened by habitat loss, hunting, and pollution.

significance to humans

Hunted for food.

Musk duck

Biziura lobata

subfamily

Oxyurinae

taxonomy

Anas lobata Shaw, 1796, New South Wales = King George Sound, Western Australia. Monotypic.

other common names

English: Lobed duck; French: Erismature à barbillons; German: Lappenente; Spanish: Malvasía de Papada.

physical characteristics

Male 26.0 in (66 cm), female 21.7 in (55 cm); male 4.0–6.9 lb (1.81–3.12 kg), female 2.2–4.1 lb (993 g–1.84 kg). Male has fleshy lobe underneath mandible.

distribution

Southwestern and southeastern Australia, Tasmania.

habitat

Freshwater wetlands with abundant reedbeds. Favors deep waters of lagoons, estuaries, and coastlines in nonbreeding season.

behavior

Males are very territorial early during the breeding season.

feeding ecology and diet

Feeds mostly by diving on aquatic invertebrates, amphibians, some fish, and small ducklings.

reproductive biology

No strong pair bond develops, probably polygamous. Breeding mostly during Sept. to Oct. Commonly lays 2–3 eggs into a concealed cup nest made of sticks and stems; incubation 24 days in captivity.

conservation status

Not threatened. Locally abundant, but generally at low abundances. May be threatened in future by habitat loss, fishing nets, and hunting.

significance to humans

Hunted for food.

Resources

Books

Batt, D. J., Alan D. Afton, Michael G. Anderson, C. Davison Ankney, Douglas H. Johson, John A. Kadlec, and Gary L. Krapu, eds. Ecology and Management of Breeding Fowl. Minneapolis: University of Minnesota Press, 1992.

del Hoyo, J., A. Elliot, and J. Sargatal, eds. Ostrich to Ducks. Vol. 1 Handbook of the Birds of the World. Barcelona: Lynx Edicions, 1992.

Johnsgard, P. A Ruddy Ducks and Other Stifftails: Their Behavior and Biology. Norman: University of Oklahoma Press, 1996.

Madge, S., and H. Burn. Waterfowl: An Identification Guide to the Ducks, Geese and Swans of the World. Boston: Houghton Mifflin, 1988.

Schneck, M. Ducks and Waterfowl. New York: Todtri Book Publishers, 2000.

Todd, Frank S. Ducks, Geese, and Swans of the World. San Diego: Seaworld, 1979.

Periodicals

Callaghan, Des A. "Conservation status of the torrent ducks Merganetta." Wildfowl 48 (1997–1998): 166–173.

Johnson, Kevin P., Frank McKinney, and Michael D. Sorenson. "Phylogenetic constraint on male parental care in dabbling ducks." Proceedings of the Royal Society of London, Series B 266 (1999): 759–763.

Livezey, Bradley C. "A phylogenetic classification of waterfowl (Aves: Anseriformes), including selected fossil species." Annals of Carnegie Museum 66 (1997): 457–496.

Olson, Storrs L. "The anseriform relationships of Antalavis Olson and Parris (Anseranatidae), with a new species from the Lower Eocene London clay." Smithsonian Contributions to Paleobiology 89 (1999): 231–243.

Organizations

Ducks Unlimited, Inc. One Waterfowl Way, Memphis, Tennessee 38120 USA. Phone: (800) 453-8257. Fax: (901) 758-3850. E-mail: [email protected] Web site: <http://www.ducks.org>

Japanese Association for Wild Geese Protection. Minamimachi 16, Wakayangi, 989-5502 Japan. Phone: +81 228 32 2004. Fax: +81 228 32 2004. E-mail: [email protected] Web site: <http://www.japwgp.org>

Other

Miyabayashi, Yoshihiko, and Taej Mundkur "Atlas of key sites for Anatidae in the East Asian flyway" <http://www.jawgp.org/anet/aaa1999/aaaendx.htm>. (1999)

Sauer, J. R., J. E. Hines, and J. Fallon. The North American Breeding Bird Survey, Results and Analyses 1966–2000. Version 2001.2. Laurel, Maryland: USGS Patuxent Wildlife Research Center, 2001.

The International Union for Conservation of Nature and Natural Resources Species Survival Commission "2000 IUCN Red List of Threatened Species" <http://www.redlist.org/>. (2000).

Markus Patricio Tellkamp, MS