Anatidae: Waterfowl
Waterfowl are a large family, among the most universally known bird categories, instantly recognizable to the vast majority of humanity. They occur essentially worldwide, wherever there are bodies of freshwater and in some marine habitats. The family includes arctic and tropical specialists, but reaches its peak diversity in temperate zones, where seasonal availability of resources in many aquatic habitats favors migratory lifestyles.
The Anatidae are diverse, from several small ducks on the scale of doves or quail up to the swans which are avian heavyweights, and all sizes in between. Most females and the males of many species have plain, mottled plumages that are the embodiment of camouflage, but many others are gaudy with multicolored plumages and unique fleshy protuberances. What they share in common, the badge of Anatidae family membership, is the benign-looking, rounded “duck bill”—in profile, a curvilinear wedge with a long, straight seam between the mandibles. Waterfowl also share basic adaptations for surface-swimming: fully webbed feet and rounded bodies with high fat content for buoyancy.
Waterfowl exploit a wide variety of food sources, animal and vegetable. At the vegetarian end of the spectrum are the geese and swans who graze constantly to sustain their bulk. At the carnivorous end are mergansers whose thin, serrated bills are designed for fishing. Filling out the middle, most waterfowl are opportunistic omnivores adapted to exploit water layers that are rich in plants and invertebrates. Most either “dabble” at the surface, tipping to forage in the shallows, or dive to graze or pursue prey at moderate depths.
Taxonomy
As currently understood, the Anatidae comprise approximately 168 to 193 species (plus 9 recently extinct) in five subfamilies, with two of those subfamilies subdivided into a total of ten tribes, as follows:
Dendrocygninae: Whistling-ducks (9 or 10 species)
Stictonettinae: Freckled Duck (1 species)
Plectropterinae: Spur-winged Goose (1 or 2 species)
Anserinae: Swans, geese, and stiff-tailed ducks (39 to 52 species)
Biziurini: Musk Duck (1 species)
Nettapodini: Pygmy-geese (3 species)
Oxyurini: Stiff-tailed ducks (8 or 9 species)
Anserini: Swans and geese (27 to 39 species)
Anatinae: Ducks (118 to 128 species, plus 9 or 10 extinct)
Tadornini: Shelducks (14 species plus 3 extinct)
Mergini: Sea-ducks (22 to 27 species plus 2 extinct)
Cairinini: Perching ducks (3 species)
Callonettini: Ringed Teal (1 species)
Aythyini: Diving ducks (23 species plus 1 extinct)
Anatini: Dabbling ducks (55 to 60 species plus 3 extinct)
The species-level taxonomy of waterfowl is stable overall. The major groups have been studied as thoroughly as any bird family—the popularity of waterfowl for recreational and subsistence hunting has guaranteed consistent funding for research—and only a few taxonomic puzzles remain.
Northern, mostly arctic-breeding geese tend to diverge into distinctive regional populations, making species boundaries ambiguous. The genera Branta and Anser were traditionally regarded as totaling 15 species, but have been reclassified as 18 and could conceivably number as many as 29. Northern sea-ducks are also in the midst of reclassification, with the scoters (Melanitta) long regarded as three species, but recently split into six, the former Common Merganser (Mergus merganser) split into two, and the Common Eider (Somateria mollissima) a candidate for subdivision into two or more species. Several South American ducks also have isolated populations that are at ambiguous stages of speciation.
White-faced Whistling-Duck (Dendrocygna viduata)
Black-bellied Whistling-Duck (Dendrocygna autumnalis)
“Northern Black-bellied Whistling-Duck” (D. a. fulgens)
“Southern Black-bellied Whistling-Duck” (D. a. autumnalis)
Spotted Whistling-Duck (Dendrocygna guttata)
West Indian Whistling-Duck (Dendrocygna arborea)
Fulvous Whistling-Duck (Dendrocygna bicolor)
Plumed Whistling-Duck (Dendrocygna eytoni)
Wandering Whistling-Duck (Dendrocygna arcuata)
Lesser Whistling-Duck (Dendrocygna javanica)
White-backed Duck (Thalassornis leuconotus)
Freckled Duck (Stictonetta naevosa)
Spur-winged Goose (Plectropterus gambensis)
“Northern Spur-winged Goose” (P. g. gambensis)
“Southern Spur-winged Goose” (P. g. niger)
Musk Duck (Biziura lobata)
African Pygmy-Goose (Nettapus auritus)
Cotton Pygmy-Goose (Nettapus coromandelianus)
Green Pygmy-Goose (Nettapus pulchellus)
Black-headed Duck (Heteronetta atricapilla)
Masked Duck (Nomonyx dominicus)
Ruddy Duck (Oxyura jamaicensis)
Andean Duck (Oxyura ferruginea)
“Colombian Duck” (O. f. andina)
“Andean Duck” (O. f. ferruginea)
Lake Duck (Oxyura vittata)
Blue-billed Duck (Oxyura australis)
Maccoa Duck (Oxyura maccoa)
White-headed Duck (Oxyura leucocephala)
Pink-eared Duck (Malacorhynchus membranaceus)
Coscoraba Swan (Coscoroba coscoroba)
Cape Barren Goose (Cereopsis novaehollandiae)
Black-necked Swan (Sthenelides melancoryphus)
Black Swan (Cygnus atratus)
Mute Swan (Cygnus olor)
Whooper Swan (Cygnus cygnus)
Trumpeter Swan (Cygnus buccinator)
Tundra Swan (Cygnus columbianus)
“Whistling Swan” (C. c. columbianus)
“Bewick’s Swan” (C. c. bewickii)
Brant (Branta bernicla)
“Dark-bellied Brant” (B. b. bernicla)
“Pale-bellied Brant” (B. b. hrota)
“Black Brant” (B. b. nigricans)
Red-breasted Goose (Branta ruficollis)
Hawaiian Goose (Branta sandvicensis)
Canada Goose (Branta canadensis)
“Greater Canada Goose” (B. c. moffitti)
“Western Canada Goose” (B. c. occidentalis)
“Lesser Canada Goose” (B. c. canadensis)
Barnacle Goose (Branta leucopsis)
Cackling Goose (Branta hutchinsii)
“Aleutian Goose” (B. h. leucopareia)
“Richardson’s Goose” (B. h. hutchinsii)
“Cackling Goose” (B. h. minima)
“Taverner’s Goose” (B. h. taverneri)
Bar-headed Goose (Anser indicus)
Emperor Goose (Anser canagicus)
Ross’s Goose (Anser rossii)
Snow Goose (Anser caerulescens)
Graylag Goose (Anser anser)
“European Graylag Goose” (A. a. anser)
“Siberian Graylag Goose” (A. a. rubrirostris)
Swan Goose (Anser cygnoides)
Lesser White-fronted Goose (Anser erythropus)
Greater White-fronted Goose (Anser albifrons)
“Greenland White-fronted Goose” (A. a. flavirostris)
“Eurasian White-fronted Goose” (A. a. albifrons)
“Gambell’s White-fronted Goose” (A. a. gambelli)
“Tule White-fronted Goose” (A. a. elgasi)
Taiga Bean Goose (Anser fabalis)
Pink-footed Goose (Anser brachyrhynchus)
Tundra Bean Goose (Anser serrirostris)
Middendorff’s Bean Goose (Anser middendorffii)
Torrent Duck (Merganetta armata)
Orinoco Goose (Neochen jubata)
Andean Goose (Chloephaga melanoptera)
Upland Goose (Chloephaga picta)
Kelp Goose (Chloephaga hybrida)
Ashy-headed Goose (Chloephaga poliocephala)
Ruddy-headed Goose (Chloephaga rubidiceps)
Raja Shelduck (Radjah radjah)
Egyptian Goose (Alopochen aegyptiaca)
Mauritius Sheldgoose (Alopochen mauritiana) †
Réunion Sheldgoose (Alopochen kervazoi) †
Common Shelduck (Tadorna tadorna)
South African Shelduck (Tadorna cana)
Ruddy Shelduck (Tadorna ferruginea)
Australian Shelduck (Tadorna tadornoides)
Paradise Shelduck (Tadorna variegata)
Crested Shelduck (Tadorna cristata) †
Harlequin Duck (Histrionicus histrionicus)
Labrador Duck (Camptorhynchus labradorius) †
Long-tailed Duck (Clangula hyemalis)
Steller’s Eider (Polysticta stelleri)
Spectacled Eider (Somateria fischeri)
King Eider (Somateria spectabilis)
Common Eider (Somateria mollissima)
“Common Eider” (S. m. mollissima)
“Faeroe Eider” (S. m. faeroeensis)
“Pacific Eider” (S. m. v-nigrum)
“Dresser’s Eider” (S. m. dresseri)
“Northern Eider” (S. m. borealis)
“Hudsonian Eider” (S. m. sedentaria)
Surf Scoter (Melanitta perspicillata)
Velvet Scoter (Melanitta fusca)
Stejneger’s Scoter (Melanitta stejnegeri)
White-winged Scoter (Melanitta deglandi)
Common Scoter (Melanitta nigra)
Black Scoter (Melanitta americana)
Bufflehead (Bucephala albeola)
Common Goldeneye (Bucephala clangula)
Barrow’s Goldeneye (Bucephala islandica)
Smew (Mergellus albellus)
Hooded Merganser (Lophodytes cucullatus)
New Zealand Merganser (Mergus australis) †
Brazilian Merganser (Mergus octosetaceus)
Common Merganser (Mergus merganser)
American Merganser (Mergus americanus)
Red-breasted Merganser (Mergus serrator)
Scaly-sided Merganser (Mergus squamatus)
Muscovy Duck (Cairina moschata)
Wood Duck (Aix sponsa)
Mandarin Duck (Aix galericulata)
Ringed Teal (Callonetta leucophrys)
Maned Duck (Chenonetta jubata)
Blue Duck (Hymenolaimus malacorhynchos)
Comb Duck (Sarkidiornis sylvicola)
Knob-billed Duck (Sarkidiornis melanotos)
Hartlaub’s Duck (Pteronetta hartlaubii)
Blue-winged Goose (Cyanochen cyanoptera)
Marbled Duck (Marmaronetta angustirostris)
White-winged Duck (Asarcornis scutulata)
Pink-headed Duck (Rhodonessa caryophyllacea) †
Red-crested Pochard (Netta rufina)
Rosy-billed Pochard (Metopiana peposaca)
Southern Pochard (Phaeoaythia erythrophthalma)
Ferruginous Duck (Aythya nyroca)
Baer’s Pochard (Aythya baeri)
Madagascan Pochard (Aythya innotata)
Hardhead (Aythya australis)
Redhead (Aythya americana)
Common Pochard (Aythya ferina)
Canvasback (Aythya valisineria)
Tufted Duck (Aythya fuligula)
New Zealand Scaup (Aythya novaeseelandiae)
Ring-necked Duck (Aythya collaris)
Greater Scaup (Aythya marila)
Lesser Scaup (Aythya affinis)
Salvadori’s Teal (Salvadorina waigiuensis)
Crested Duck (Lophonetta specularioides)
Brazilian Teal (Amazonetta brasiliensis)
Bronze-winged Duck (Speculanas specularis)
Flying Steamer-Duck (Tachyeres patachonicus)
Fuegian Steamer-Duck (Tachyeres pteneres)
Falkland Steamer-Duck (Tachyeres brachypterus)
Chubut Steamer-Duck (Tachyeres leucocephalus)
Baikal Teal (Sibirionetta formosa)
Garganey (Spatula querquedula)
Hottentot Teal (Spatula hottentota)
Puna Teal (Spatula puna)
Silver Teal (Spatula platalea)
Red Shoveler (Spatula versicolor)
Blue-winged Teal (Spatula discors)
Cinnamon Teal (Spatula cyanoptera)
Cape Shoveler (Spatula smithii)
Northern Shoveler (Spatula clypeata)
Australasian Shoveler (Spatula rhynchotis)
Gadwall (Mareca strepera)
Falcated Duck (Mareca falcata)
Eurasian Wigeon (Mareca penelope)
Amsterdam Island Wigeon (Mareca marecula) †
American Wigeon (Mareca americana)
Chiloé Wigeon (Mareca sibilatrix)
African Black Duck (Anas sparsa)
Yellow-billed Duck (Anas undulata)
Meller’s Duck (Anas melleri)
Philippine Duck (Anas luzonica)
Pacific Black Duck (Anas superciliosa)
Laysan Duck (Anas laysanensis)
Hawaiian Duck (Anas wyvilliana)
Indian Spot-billed Duck (Anas poecilorhyncha)
Mallard (Anas platyrhynchos)
Eastern Spot-billed Duck (Anas zonorhyncha)
American Black Duck (Anas rubripes)
Mexican Duck (Anas diazi)
Mottled Duck (Anas fulvigula)
“Mexican Mottled Duck” (A. f. fulvigula)
“Florida Mottled Duck” (A. f. maculosa)
Eurasian Teal (Anas crecca)
Green-winged Teal (Anas carolinensis)
Andean Teal (Anas andium)
“Mérida Teal” (A. a. altipetens)
“Andean Teal” (A. a. andium)
Yellow-billed Teal (Anas flavirostris)
“Andean Yellow-billed Teal” (A. f. oxyptera)
“Patagonian Yellow-billed Teal” (A. f. flavirostris)
Cape Teal (Anas capensis)
Red-billed Teal (Anas erythrorhyncha)
White-cheeked Pintail (Anas bahamensis)
“White-cheeked Pintail” (A. b. bahamensis)
“Galápagos Pintail” (A. b. galapagensis)
Yellow-billed Pintail (Anas georgica)
“South Georgia Pintail” (A. g. georgica)
“Yellow-billed Pintail” (A. g. spinicauda)
Northern Pintail (Anas acuta)
Eaton’s Pintail (Anas eatoni)
Chestnut Teal (Anas castanea)
Andaman Teal (Anas albogularis)
Sunda Teal (Anas gibberifrons)
Gray Teal (Anas gracilis)
Bernier’s Teal (Anas bernieri)
Mascarene Teal (Anas theodori) †
Chatham Duck (Anas chathamica) †
Brown Teal (Anas chlorotis)
Auckland Teal (Anas aucklandica)
Campbell Teal (Anas nesiotis)
References
Boyd, J.H., 2017. Taxonomy in Flux: ANSERIFORMES: Waterfowl. http://jboyd.net/Taxo/List1a.html#anseriformes. (Posted July 12, 2017. Accessed December 27, 2020.)
Hume, J.P. 2017. Extinct Birds (Second Edition). Bloomsbury Publishing PLC, London.
Reeber, S. 2015. Waterfowl of North America, Europe & Asia: An Identification Guide. Princeton University Press.
Roberson, D. 2008. Bird Families of the World: Ducks, Geese & Swans: Anatidae, http://creagrus.home.montereybay.com/ducks.html. (Posted July 4, 2008. Accessed December 28, 2020.)
Text © Russell Fraker / December 28, 2020