Anatidae

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{{Taxobox | color = pink | name = Ducks | image = white-fronted.goose.2.750pix.jpg | image_width = 200px | image_caption = White-fronted Goose (Anser albifrons) | regnum = Animalia | phylum = Chordata | classis = Aves | ordo = Anseriformes | familia = Anatidae | familia_authority = Vigors, 1825 | subdivision_ranks = Subfamilies | subdivision = Dendrocygninae
Thalassorninae
Anserinae
Stictonettinae
Plectropterinae
Tadorninae
Anatinae
Merginae
Oxyurinae }} Anatidae is the biological family that includes the ducks and most duck-like waterfowl, such as geese and swan. The Magpie-goose is no longer considered to be part of the Anatidae, but is placed in its own family Anseranatidae. These are birds that are modified for swimming, floating on the water surface, and in some cases diving in at least shallow water.

They have webbed feet and bills which are flattened to a greater or lesser extent. Their feathers are excellent at shedding water due to special oils. Anatidae are remarkable for being one of the few families of birds that possess a penis; they are adapted for copulation on the water only and care must be taken when breeding ducks or geese that a pool is provided for this purpose as attempts to copulate on dry land will often lead to injury of the drake's penis. Duck, eider and goose feathers and down have long been popular for bedspreads, pillows, sleeping bags and coats. The members of this family also have long been used for food.

While the status of the Anatidae as a family is straightforward, and there is little debate about which species properly belong to it, the relationships of the different tribes and subfamilies within it are poorly understood. The listing in the box at right should be regarded simply one of several possible ways of organising the many species within the Anatidae.

1 Classification
2 References
3 External links

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Classification

Previously divided into six subfamilies, recent anatomical studies by Livezey (1986; A phylogenetic analysis of recent Anseriform genera, Auk 103: 737-754) showed that the Anatidae are better treated in nine subfamilies. This classification has been followed by Madge & Burn:

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Dendrocygninae: whistling ducks

One pantropical genus, of distinctive long-legged goose-like birds:
- Dendrocygna (whistling ducks, 9 species)

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Thalassorninae: White-backed Duck

One genus in Africa, most closely related to the subfamily Dendrocygninae, though also showing convergent similarities to the subfamily Oxyurinae:
- Thalassornis (White-backed Duck, 1 species)

Image:Mute.swan.flaps.arp.750pix.jpg

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Anserinae: swans and geese

Five to seven extant genera with 27 living species, mainly cool temperate Northern Hemisphere but also some Southern Hemisphere species, with the swans in two genera (three genera in some treatments), and the geese in four genera (three genera in some treatments):
- Coscoroba (Coscoroba Swan, 1 species)
- Cygnus (swans, 7 species, 4 sometimes separated in Olor)
- Anser (grey geese, 7 species)
- Chen (white geese, 3 species)
- Branta (black geese, 8 living species)
- Cereopsis (Cape Barren Goose, 1 species, sometimes transferred to Tadorninae)
- Cnemiornis (New Zealand Geese, extinct)

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Stictonettinae: Freckled Duck

One genus in Australia, formerly included in the Oxyurinae, but with anatomy suggesting a distinct ancient lineage perhaps closest to the Anserinae:
- Stictonetta (Freckled Duck, 1 species)

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Plectropterinae: Spur-winged Goose

One genus in Africa, formerly included in the 'perching ducks', but closer to the Tadorninae:
- Plectropterus (Spur-winged Goose, 1 species)

Image:Coscoroba.swan.arp.750pix.jpg

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Tadorninae: shelducks, sheldgeese and steamer-ducks

This group of larger, often semi-terrestrial waterfowl can be seen as intermediate between Anserinae and Anatinae. Recent revision has resulted in the inclusion of 10 extant genera with 23 living species (one probably extinct) in this subfamily, mostly from the Southern Hemisphere but a few in the Northern Hemisphere:
- Sarkidiornis (Comb Duck, 1 species)
- Pachyanas (Chatham Island Duck, extinct)
- Tadorna (shelducks, 7 species, one probably extinct)
- Hymenolaimus (Pink-eared Ducks, 1 living species)
- Centrornis (Madagascar Sheldgoose, extinct)
- Alopochen (Egyptian Goose and Mascarene Shelducks, 1 living species)
- Neochen (Orinoco Goose, 1 species)
- Chloephaga (sheldgeese, 5 species)
- Cyanochen (Blue-winged Goose, 1 species)
- Hymenolaimus (Blue Duck, 1 species)
- Merganetta (Torrent Duck, 1 species)
- Tachyeres (steamer ducks, 4 species)

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Anatinae: dabbling and diving ducks and moa-nalos

The dabbling duck group, of worldwide distribution, were previously restricted to just one or two genera, but has now been extended to include 8 extant genera and about 55 living species, including several genera formerly known as the "perching ducks":
- Pteronetta (Hartlaub's Duck, 1 species)
- Cairina (Muscovy Duck and White-winged Wood Duck, 2 species)
- Aix (Mandarin Duck and Wood Duck, 2 species)
- Nettapus (pygmy geese, 3 species)
- Anas (wigeons, gadwalls, teals, pintails, mallards, shovelers, etc, 40-45 living species)
- Callonetta (Ringed Teal, 1 species)
- Chenonetta (Maned Duck, 1 living species)
- Amazonetta (Brazilian Duck, 1 species)
The moa-nalos, of which 4 species in 3 genera are known to date, are a peculiar group of flightless, extinct Anatidae from the Hawaiian Islands. Gigantic in size and with massive bills, they were believed to be geese, but have been shown to be in reality very closely related to the genus Anas. They have evolved fill the ecological niche of turtles, ungulates and other megaherbivores.
- Chelychelynechen (Turtle-jawed Moa-nalo, extinct)
- Thambetochen (Large-billed Moa-nalos, 2 species, extinct)
- Ptaiochen (Small-billed Moa-nalo, extinct)
The 16 species of diving ducks, of worldwide distribution, in 3 genera; Marmaronetta was formerly included with the dabbling ducks but is now treated here, and genetic analysis of the probably extinct Pink-headed Duck of India, previously treated separately in Rhodonessa, has shown that it is better placed in Netta:
- Marmaronetta (Marbled Duck, 1 species)
- Netta (Red-crested Pochard and allies, 4 species, one probably extinct)
- Aythya (pochards, scaups, etc, 12 species, one probably extinct)

Image:Red-crested.pochard.2.arp.750pix.jpg

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Merginae: eiders, scoters, sawbills and other sea-ducks

There are 10 extant genera and 20 living species (one or two extinct); most of this group occur in the Northern Hemisphere, but two Mergus in the Southern Hemisphere:
- Chendytes (Diving-geese, extinct)
- Polysticta (Steller's Eider, 1 species)
- Somateria (eiders, 3 species)
- Histrionicus (Harlequin Duck, 1 species)
- Camptorhynchus (Labrador Duck, extinct)
- Melanitta (scoters, 3 species)
- Clangula (Long-tailed Duck, 1 species)
- Bucephala (goldeneyes, 3 species)
- Mergellus (Smew, 1 species)
- Lophodytes (Hooded Merganser, 1 species)
- Mergus (mergansers, 5 species, one extinct).

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Oxyurinae: stiff-tail ducks

A small group of 4 genera, 3 of them monotypic, with 8 living species:
- Oxyura (stiff-tailed ducks, 6 species)
- Biziura (Musk Ducks, 1 living species)
- Heteronetta (Black-headed Duck, 1 species)

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