The Anatidae are the biological family of

water bird A water bird, alternatively waterbird or aquatic bird, is a bird that lives on or around water. In some definitions, the term ''water bird'' is especially applied to birds in freshwater ecosystems, although others make no distinction from sea ...

s that includes ducks,

geese A goose ( : geese) is a bird of any of several waterfowl species in the family Anatidae. This group comprises the genera '' Anser'' (the grey geese and white geese) and ''Branta'' (the black geese). Some other birds, mostly related to the sh ...

, and swans. The family has a cosmopolitan distribution, occurring on all the world's continents except Antarctica. These

bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight ...

s are adapted for

swimming Swimming is the self-propulsion of a person through water, or other liquid, usually for recreation, sport, exercise, or survival. Locomotion is achieved through coordinated movement of the limbs and the body to achieve hydrodynamic thrust that ...

, floating on the water surface, and in some cases diving in at least shallow water. The family contains around 174 species in 43 genera. (The

magpie goose The magpie goose (''Anseranas semipalmata'') is the sole living representative species of the family Anseranatidae. This common waterbird is found in northern Australia and southern New Guinea. As the species is prone to wandering, especially ...

is no longer considered to be part of the Anatidae and is now placed in its own family, Anseranatidae.) They are generally herbivorous, and are

monogamous Monogamy ( ) is a form of dyadic relationship in which an individual has only one partner during their lifetime. Alternately, only one partner at any one time (serial monogamy) — as compared to the various forms of non-monogamy (e.g., pol ...

breeders. A number of species undertake annual migrations. A few species have been domesticated for agriculture, and many others are hunted for food and recreation. Five species have become extinct since 1600, and many more are

threatened Threatened species are any species (including animals, plants and fungi) which are vulnerable to endangerment in the near future. Species that are threatened are sometimes characterised by the population dynamics measure of '' critical depe ...

with extinction. Mallard drake in flight

Description and ecology

The ducks, geese, and swans are small- to large-sized birds with a broad and elongated general body plan. Diving species vary from this in being rounder. Extant species range in size from the

cotton pygmy goose The cotton pygmy goose or cotton teal (''Nettapus coromandelianus'') is a small perching duck which breeds in Asia, Southeast Asia extending south and east to Queensland where they are sometimes called white-quilled pygmy goose. They are among t ...

, at as little as 26.5 cm (10.5 in) and 164 g (5.8 oz), to the

trumpeter swan The trumpeter swan (''Cygnus buccinator'') is a species of swan found in North America. The heaviest living bird native to North America, it is also the largest extant species of waterfowl, with a wingspan of 185 to 250 cm (6 ft 2 in to 8 ft 2 ...

, at as much as 183 cm (6 ft) and 17.2 kg (38 lb). The wings are short and pointed, and supported by strong wing muscles that generate rapid beats in

flight Flight or flying is the process by which an object moves through a space without contacting any planetary surface, either within an atmosphere (i.e. air flight or aviation) or through the vacuum of outer space (i.e. spaceflight). This can be ...

. They typically have long necks, although this varies in degree between species. The legs are short, strong, and set far to the back of the body (more so in the more aquatic species), and have a leathery feel with a scaly texture. Combined with their body shape, this can make some species awkward on land, but they are stronger walkers than other marine and water birds such as

grebe Grebes () are aquatic diving birds in the order Podicipediformes . Grebes are widely distributed freshwater birds, with some species also found in marine habitats during migration and winter. Some flightless species exist as well, most notably ...

s or

petrel Petrels are tube-nosed seabirds in the bird order Procellariiformes. Description The common name does not indicate relationship beyond that point, as "petrels" occur in three of the four families within that group (all except the albatross ...

s. They typically have webbed feet, though a few species such as the Nene have secondarily lost their webbing. The bills are made of soft keratin with a thin and sensitive layer of skin on top (which has a leathery feel when touched). For most species, the shape of the bill tends to be more flattened to a greater or lesser extent. These contain serrated

lamellae Lamella (plural lamellae) means a small plate or flake in Latin, and in English may refer to: Biology * Lamella (mycology), a papery rib beneath a mushroom cap * Lamella (botany) * Lamella (surface anatomy), a plate-like structure in an animal * ...

which are particularly well defined in the filter-feeding species. Their feathers are excellent at shedding water due to special oils. Many of the ducks display sexual dimorphism, with the males being more brightly coloured than the females (although the situation is reversed in species such as the paradise shelduck). The swans, geese, and whistling-ducks lack sexually dimorphic plumage. Anatids are vocal birds, producing a range of quacks, honks, squeaks, and trumpeting sounds, depending on species; the female often has a deeper voice than the male. Anatids are generally herbivorous as adults, feeding on various water-plants, although some species also eat fish, molluscs, or aquatic arthropods. One group, the mergansers, are primarily

piscivorous A piscivore () is a carnivorous animal that eats primarily fish. The name ''piscivore'' is derived . Piscivore is equivalent to the Greek-derived word ichthyophage, both of which mean "fish eater". Fish were the diet of early tetrapod evolut ...

, and have serrated bills to help them catch fish. In a number of species, the young include a high proportion of invertebrates in their diets, but become purely herbivorous as adults.

Breeding

The anatids are generally seasonal and

breeders. The level of monogamy varies within the family; many of the smaller ducks only maintain the bond for a single season and find a new partner the following year, whereas the larger swans, geese and some of the more territorial ducks maintain pair bonds over a number of years, and even for life in some species. However, forced extrapair copulation among anatids is common, occurring in 55 species in 17 genera. Anatidae is a large proportion of the 3% of bird species to possess a penis, though they vary significantly in size, shape, and surface elaboration. Most species are adapted for

copulation Sexual intercourse (or coitus or copulation) is a sexual activity typically involving the insertion and thrusting of the penis into the vagina for sexual pleasure or reproduction.Sexual intercourse most commonly means penile–vaginal penetr ...

on the water only. They construct simple nests from whatever material is close at hand, often lining them with a layer of down plucked from the mother's breast. In most species, only the female incubates the eggs. The young are

precocial In biology, altricial species are those in which the young are underdeveloped at the time of birth, but with the aid of their parents mature after birth. Precocial species are those in which the young are relatively mature and mobile from the mome ...

, and are able to feed themselves from birth. One aberrant species, the black-headed duck, is an obligate

brood parasite Brood parasites are animals that rely on others to raise their young. The strategy appears among birds, insects and fish. The brood parasite manipulates a host, either of the same or of another species, to raise its young as if it were its ...

, laying its eggs in the nests of

gull Gulls, or colloquially seagulls, are seabirds of the family Laridae in the suborder Lari. They are most closely related to the terns and skimmers and only distantly related to auks, and even more distantly to waders. Until the 21st century, m ...

s and

coot Coots are medium-sized water birds that are members of the rail family, Rallidae. They constitute the genus ''Fulica'', the name being the Latin term for "coot". Coots have predominantly black plumage, and—unlike many rails—they are usua ...

s. While this species never raises its own young, a number of other ducks occasionally lay eggs in the nests of conspecifics (members of the same species) in addition to raising their own broods.

Relationship with humans

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. Humans have had a long relationship with ducks, geese, and swans; they are important economically and culturally to humans, and several duck species have benefited from an association with people. However, some anatids are damaging

agricultural Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled people to ...

pests, and have acted as vectors for zoonoses such as

avian influenza Avian influenza, known informally as avian flu or bird flu, is a variety of influenza caused by viruses adapted to birds.

. Since 1600, five species of ducks have become extinct due to the activities of humans, and subfossil remains have shown that humans caused numerous extinctions in prehistory. Today, many more are considered

. Most of the historic and prehistoric extinctions were insular species, vulnerable due to small populations (often

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...

to a single island), and

island tameness Island tameness is the tendency of many populations and species of animals living on isolated islands to lose their wariness of potential predators, particularly of large animals. The term is partly synonymous with ecological naïveté, which also ...

. Evolving on islands that lacked predators, these species lost antipredator behaviours, as well as the ability to fly, and were vulnerable to human hunting pressure and introduced species. Other extinctions and declines are attributable to overhunting,

habitat loss Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby ...

and modification, and hybridisation with introduced ducks (for example the introduced ruddy duck swamping the white-headed duck in Europe). Numerous governments and conservation and hunting organisations have made considerable progress in protecting ducks and duck populations through habitat protection and creation, laws and protection, and captive-breeding programmes.

Systematics

The name Anatidae for the family was introduced by the English zoologist William Elford Leach in a guide to the contents of the

British Museum The British Museum is a public museum dedicated to human history, art and culture located in the Bloomsbury area of London. Its permanent collection of eight million works is among the largest and most comprehensive in existence. It docume ...

published in 1820. While the status of the Anatidae as a family is straightforward, and which species properly belong to it is little debated, the relationships of the different tribes and subfamilies within it are poorly understood. The listing in the box at right should be regarded as simply one of several possible ways of organising the many species within the Anatidae; see discussion in the next section. The systematics of the Anatidae are in a state of flux. Previously divided into six subfamilies, a study of anatomical characters by Livezey suggests the Anatidae are better treated in nine subfamilies. This classification was popular in the late 1980s to 1990s. But

mtDNA Mitochondrial DNA (mtDNA or mDNA) is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, such as adenosine triphosphate (ATP). Mitochondrial ...

sequence In mathematics, a sequence is an enumerated collection of objects in which repetitions are allowed and order matters. Like a set, it contains members (also called ''elements'', or ''terms''). The number of elements (possibly infinite) is calle ...

analyses indicate, for example, the dabbling and diving ducks do not belong in the same subfamily. While shortcomings certainly occur in Livezey's analysis, mtDNA is an unreliable source for phylogenetic information in many waterfowl (especially dabbling ducks) due to their ability to produce fertile hybrids, in rare cases possibly even beyond the level of genus (see for example the " Barbary duck"). Because the

sample size Sample size determination is the act of choosing the number of observations or replicates to include in a statistical sample. The sample size is an important feature of any empirical study in which the goal is to make inferences about a populatio ...

of many molecular studies available to date is small, mtDNA results must be considered with caution. While a comprehensive review of the Anatidae which unites all evidence into a robust phylogeny is still lacking, the reasons for the confusing data are at least clear: As demonstrated by the Late Cretaceous fossil '' Vegavis iaai'' — an early modern waterbird which belonged to an extinct lineage—the Anatidae are an ancient group among the modern birds. Their earliest direct ancestors, though not documented by fossils yet, likewise can be assumed to have been contemporaries with the non-avian

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is ...

s. The long period of evolution and shifts from one kind of waterbird lifestyle to another have obscured many

plesiomorph In phylogenetics, a plesiomorphy ("near form") and symplesiomorphy are synonyms for an ancestral character shared by all members of a clade, which does not distinguish the clade from other clades. Plesiomorphy, symplesiomorphy, apomorphy, ...

ies, while

apomorph In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to h ...

ies apparently are quite often the result of

parallel evolution Parallel evolution is the similar development of a trait in distinct species that are not closely related, but share a similar original trait in response to similar evolutionary pressure.Zhang, J. and Kumar, S. 1997Detection of convergent and paral ...

, for example the "non-diving duck" type displayed by such unrelated genera as '' Dendrocygna'', ''

Amazonetta The Brazilian teal or Brazilian duck (''Amazonetta brasiliensis'') is the only duck in the genus ''Amazonetta''. It is widely distributed in eastern South America. Taxonomy The Brazilian teal was formally described in 1789 by the German natur ...

'', and ''

Cairina The Muscovy duck (''Cairina moschata'') is a large duck native to the Americas, from the Rio Grande Valley of Texas and Mexico south to Argentina and Uruguay. Small wild and feral breeding populations have established themselves in the Unite ...

''. For the fossil record, see below. Alternatively, the Anatidae may be considered to consist of three subfamilies (ducks, geese, and swans, essentially) which contain the groups as presented here as

tribe The term tribe is used in many different contexts to refer to a category of human social group. The predominant worldwide usage of the term in English is in the discipline of anthropology. This definition is contested, in part due to conf ...

s, with the swans separated as subfamily Cygninae, the goose subfamily Anserinae also containing the whistling ducks, and the Anatinae containing all other

clades A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

Genera

For the living and recently extinct members of each genus, see the article List of Anatidae species. * Subfamily: Dendrocygninae (one pantropical genus, of distinctive long-legged goose-like birds) ** '' Dendrocygna'', whistling ducks (8 living species) ** '' Thalassornis'',

white-backed duck The white-backed duck (''Thalassornis leuconotus'') is a waterbird of the family Anatidae. It is distinct from all other ducks, but most closely related to the whistling ducks in the subfamily Dendrocygninae, though also showing some similaritie ...

* Subfamily:

Anserinae The Anserinae are a subfamily in the waterfowl family Anatidae. It includes the swans and true geese. Under alternative systematical concepts (see e.g., Terres & NAS, 1991), it is split into two subfamilies, the Anserinae contain the geese a ...

, swans and geese (3–7 extant genera with 25–30 living species, mainly cool temperate Northern Hemisphere, but also some Southern Hemisphere species, with the swans in one genus wo genera in some treatments and the

in three genera wo genera in some treatments Some other species are sometimes placed herein, but seem somewhat more distinct

below Below may refer to: * Earth * Ground (disambiguation) * Soil *Floor * Bottom (disambiguation) *Less than * Temperatures below freezing * Hell or underworld People with the surname *Ernst von Below (1863–1955), German World War I general *Fred ...

]) ** ''Swan, Cygnus'', true swans (6 species, 4 sometimes separated in ''Olor'') ** ''Anser (bird), Anser'', grey geese and white geese (11 species) ** ''Branta'', black geese (6 living species) * Subfamily: Stictonettinae (one genus in Australia, formerly included in the Oxyurinae, but with anatomy suggesting a distinct ancient lineage perhaps closest to the Anserinae, especially the

Cape Barren goose The Cape Barren goose (''Cereopsis novaehollandiae'') is a large goose resident in southern Australia. Etymology The species' common name is derived from Cape Barren Island, where specimens were first sighted by European explorers. It is known ...

) ** '' Stictonetta'', freckled duck * Subfamily: Plectropterinae (one genus in Africa, formerly included in the "perching ducks", but closer to the Tadorninae) ** '' Plectropterus'', spur-winged goose * Subfamily: Tadorninae – shelducks and sheldgeese Common

(This group of larger, often semiterrestrial waterfowl can be seen as intermediate between Anserinae and Anatinae. The 1986 revision has resulted in the inclusion of 10 extant genera with about two-dozen living species ne probably extinctin this subfamily, mostly from the Southern Hemisphere but a few in the Northern Hemisphere; the affiliations of several presumed tadornine genera has later been questioned and the group in the traditional lineup is likely to be paraphyletic.) ** '' Pachyanas'', Chatham Island duck (

prehistoric Prehistory, also known as pre-literary history, is the period of human history between the use of the first stone tools by hominins 3.3 million years ago and the beginning of recorded history with the invention of writing systems. The use ...

) ** ''

Tadorna The shelducks, most species of which are found in the genus ''Tadorna'' (except for the Radjah shelduck, which is now found in its own monotypic genus ''Radjah''), are a group of large birds in the Tadorninae subfamily of the Anatidae, the biolog ...

'', shelducks (6 species, 1 probably extinct) – possibly paraphyletic ** ''

Radjah The radjah shelduck (''Radjah radjah''), is a species of shelduck found mostly in New Guinea and Australia, and also on some of the Moluccas. It is known alternatively as the raja shelduck, black-backed shelduck, or in Australia as the Burdekin ...

'', Radjah shelduck ** '' Salvadorina'', Salvadori's teal ** '' Centrornis'', Madagascar sheldgoose (

, tentatively placed here) ** '' Alopochen'', Egyptian goose and Mascarene shelducks (1 living species, 2 extinct) ** '' Neochen'', (2 species) ** '' Chloephaga'', sheldgeese (4 species) ** ''

Hymenolaimus The blue duck or whio (''Hymenolaimus malacorhynchos'') is a member of the duck, goose and swan family Anatidae endemic to New Zealand. It is the only member of the genus ''Hymenolaimus''. Its exact taxonomic status is still unresolved, but i ...

'', blue duck ** ''

Merganetta The torrent duck (''Merganetta armata'') is a member of the duck, goose and swan family Anatidae. It is the only member of the genus ''Merganetta''. It is placed in the shelduck subfamily Tadorninae after the " perching duck" assemblage to whic ...

'', torrent duck Male mallard duck 2

* Subfamily: Aythyinae, diving ducks (Some 15 species of diving ducks, of worldwide distribution, in two to four genera; The 1986 morphological analysis suggested the probably extinct

pink-headed duck The pink-headed duck (''Rhodonessa caryophyllacea'') is a large diving duck that was once found in parts of the Gangetic plains of India, parts of Maharashtra, Bangladesh and in the riverine swamps of Myanmar but feared extinct since the 1950s. N ...

of India, previously treated separately in ''Rhodonessa'', should be placed in ''Netta'', but this has been questioned. Furthermore, while morphologically close to dabbling ducks, the mtDNA data indicate a treatment as distinct subfamily is indeed correct, with the Tadorninae being actually closer to dabbling ducks than the diving ducks) ** ''

Netta ''Netta'' is a genus of diving ducks. The name is derived from Greek ''Netta'' "duck". Unlike other diving ducks, the ''Netta'' species are reluctant to dive, and feed more like dabbling ducks. These are gregarious ducks, mainly found on fresh ...

'', red-crested pochard and allies (4 species, 1 probably extinct) ** ''

Aythya ''Aythya'' is a genus of diving ducks. It has twelve described species. The name ''Aythya'' comes from the Ancient Greek word (), which may have referred to a sea-dwelling duck or an auklet. ''Aythya shihuibas'' was described from the Late Mi ...

'', pochards, scaups, etc. (12 species) * Subfamily: Anatinae, dabbling ducks and moa-nalos (The dabbling duck group, of worldwide distribution, were previously restricted to just one or two genera, but had been extended to include eight extant genera and about 55 living species, including several genera formerly known as the "perching ducks"; mtDNA on the other hand confirms that the genus ''Anas'' is over-lumped and casts doubt on the diving duck affiliations of several genera ee below The

moa-nalo The moa-nalo are a group of extinct aberrant, goose-like ducks that lived on the larger Hawaiian Islands, except Hawaii itself, in the Pacific. They were the major herbivores on most of these islands until they became extinct after human settle ...

s, of which four species in three genera are known to date, are a peculiar group of flightless, extinct anatids from the Hawaiian Islands. Gigantic in size and with massive bills, they were believed to be geese, but have been shown to be actually very closely related to

mallard The mallard () or wild duck (''Anas platyrhynchos'') is a dabbling duck that breeds throughout the temperate and subtropical Americas, Eurasia, and North Africa, and has been introduced to New Zealand, Australia, Peru, Brazil, Uruguay, Arge ...

s. They evolved filling the ecological niche of

turtles Turtles are an order of reptiles known as Testudines, characterized by a special shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Cryptodira (hidden necked tu ...

ungulates Ungulates ( ) are members of the diverse clade Ungulata which primarily consists of large mammals with hooves. These include odd-toed ungulates such as horses, rhinoceroses, and tapirs; and even-toed ungulates such as cattle, pigs, giraffes, cam ...

, and other megaherbivores. ** ''

Anas ''Anas'' is a genus of dabbling ducks. It includes the pintails, most teals, and the mallard and its close relatives. It formerly included additional species but following the publication of a molecular phylogenetic study in 2009 the genus was s ...

'': pintails, mallards, etc. (40–50 living species, 3 extinct) ** ''

Chendytes ''Chendytes lawi'' is an extinct, goose-sized flightless marine duck, once common on the California coast, the California Channel Islands, and possibly southern Oregon. It lived in the Pleistocene and survived into the Holocene. It appears to ha ...

'', diving-geese (extinct c. 450–250 BCE, A basal member of the dabbling duck clade) ** ''

Spatula A spatula is a broad, flat, flexible blade used to mix, spread and lift material including foods, drugs, plaster and paints. In medical applications, "spatula" may also be used synonymously with tongue depressor. The word ''spatula'' derives f ...

'', shovelers ** '' Mareca'', wigeons and gadwalls ** '' Lophonetta'', crested duck ** '' Speculanas'', bronze-winged duck ** ''

'', Brazilian teal ** '' Sibirionetta'', Baikal teal ** '' Chelychelynechen'', turtle-jawed moa-nalo (

) ** ''

Thambetochen Thambetochen is an extinct genus of moa-nalo duck. It contains two species, the Maui Nui moa-nalo (''T. chauliodous'') and the smaller O'ahu moa-nalo (''T. xanion''). The former was found on Maui and Molokai on Hawaii, the latter was f ...

'', large-billed moa-nalos (2 species,

) ** '' Ptaiochen'', small-billed moa-nalo (

) * Tribe:

Mergini The sea ducks (''Mergini'') are a tribe of the duck subfamily of birds, the Anatinae. The taxonomy of this group is incomplete. Some authorities separate the group as a subfamily, while others remove some genera. Most species within the group ...

, eiders, scoters, sawbills and other sea-ducks Bucephala clangula ja 01

(There are 9 extant genera and some 20 living species; most of this group occur in the Northern Hemisphere, but a few ostly extinctmergansers in the Southern Hemisphere) ** '' Shiriyanetta'' (

) ** '' Polysticta'', Steller's eider ** ''

Somateria Eiders () are large seaducks in the genus ''Somateria''. The three extant species all breed in the cooler latitudes of the Northern Hemisphere. The down feathers of eider ducks, and some other ducks and geese, are used to fill pillows and quil ...

'', eiders (3 species) ** ''

Histrionicus The harlequin duck (''Histrionicus histrionicus'') is a small sea duck. It takes its name from Harlequin (French ''Arlequin'', Italian ''Arlecchino''), a colourfully dressed character in Commedia dell'arte. The species name comes from the Lat ...

'', harlequin duck (includes ''Ocyplonessa'') ** '' Camptorhynchus'', Labrador duck ( extinct) ** ''

Melanitta The scoters are stocky seaducks in the genus ''Melanitta''. The drakes are mostly black and have swollen bills, the females are brown. They breed in the far north of Europe, Asia, and North America, and winter farther south in temperate zones ...

'', scoters (6 species) ** ''

Clangula The long-tailed duck (''Clangula hyemalis''), formerly known as oldsquaw, is a medium-sized sea duck that breeds in the tundra and taiga regions of the arctic and winters along the northern coastlines of the Atlantic and Pacific Oceans. It is th ...

'', long-tailed duck (1 species) ** '' Bucephala'', goldeneyes (3 species) ** ''

Mergellus ''Mergellus'' is a genus of duck. The smew ''(Mergellus albellus)'' is the only living species, but an extinct species known as '' Mergellus mochanovi'' has also been described from Late Pleistocene deposits in the Yakutia Sakha, officially ...

'', smew ** ''

Lophodytes The hooded merganser (''Lophodytes cucullatus'') is a species of merganser. It is the only extant species in the genus ''Lophodytes''. The genus name derives from the Greek language: ''lophos'' meaning 'crest', and ''dutes'' meaning 'diver'. ...

'', hooded merganser ** ''

Mergus ''Mergus'' is the genus of the typical mergansers , fish-eating ducks in the subfamily Anatinae. The genus name is a Latin word used by Pliny the Elder and other Roman authors to refer to an unspecified waterbird. The common merganser ('' ...

'', mergansers (4 living species, 1 extinct). * Tribe: Oxyurini, stiff-tail ducks (a small group of 3–4 genera, 2–3 of them monotypic, with 7–8 living species) ** '' Oxyura'', stiff-tailed ducks (5 living species) ** '' Nomonyx'', masked duck ** '' Heteronetta'', black-headed duck * Unresolved: The largest degree of uncertainty concerns whether a number of genera are closer to the shelducks or to the dabbling ducks. White-winged

Prehistoric species

From subfossil bones found on

Kauai Kauai, () anglicized as Kauai ( ), is geologically the second-oldest of the main Hawaiian Islands (after Niʻihau). With an area of 562.3 square miles (1,456.4 km2), it is the fourth-largest of these islands and the 21st largest islan ...

( Hawaiian Islands), two enigmatic waterfowl are known. The living and assignable prehistoric avifauna of the

archipelago An archipelago ( ), sometimes called an island group or island chain, is a chain, cluster, or collection of islands, or sometimes a sea containing a small number of scattered islands. Examples of archipelagos include: the Indonesian Archi ...

contains as Anseriformes ''Branta'' geese and their descendants, and the

s as mentioned above. The following taxa, although certainly new species, cannot be assigned even to subfamily; that Kauai is the oldest of the large Hawaiian Islands, meaning the species may have been evolving in isolation for nearly 10 mya (since the Late Miocene), does not help in determining their affinities: * Long-legged "shelduck", Anatidae sp. et gen. indet. * Kaua'i mole duck, ''Talpanas lippa'' Similarly, '' Branta rhuax'' from the Big Island of Hawaii, and a gigantic goose-like anatid from

Oahu Oahu () ( Hawaiian: ''Oʻahu'' ()), also known as "The Gathering Place", is the third-largest of the Hawaiian Islands. It is home to roughly one million people—over two-thirds of the population of the U.S. state of Hawaii. The island of O ...

are known only from very incomplete, and in the former case much damaged, bone fragments. The former has been alleged to be a shelduck, but this was generally dismissed because of the damage to the material and

biogeographic Biogeography is the study of the distribution of species and ecosystems in geographic space and through geological time. Organisms and biological communities often vary in a regular fashion along geographic gradients of latitude, elevation, ...

considerations. The long-legged Kauai bird, however, hints at the possibility of a former tadornine presence on the archipelago.

Fossil Anatidae

The fossil record of anatids is extensive, but many prehistoric genera cannot be unequivocally assigned to present-day subfamilies for the reasons given above. For prehistoric species of extant genera, see the respective genus accounts. Dendrocheninae – a more advanced relative of the whistling-ducks or an ancestral relative of stifftail ducks paralleling whistling-ducks; if not extinct possibly belong in Oxyurinae (including '' Malacorhynchus'') * '' Mionetta'' (Late Oligocene – Middle Miocene of C Europe) – includes ''"Anas" blanchardi'', ''"A." consobrina'', ''"A." natator'', ''"Aythya" arvernensis'' * '' Manuherikia'' (Bathans Early/Middle Miocene of Otago, New Zealand) * '' Dendrochen'' (Early – Late? Miocene) – includes ''"Anas" integra'', ''"A." oligocaena'' * Dendrocheninae gen. et sp. indet. (Late Miocene of Argentina) Black Swan skeleton

* '' Cygnavus'' (Early Oligocene of Kazakhstan – Early Miocene of Germany) * '' Cygnopterus'' (Middle Oligocene of Belgium – Early Miocene of France) – sometimes included in ''Cygnavus'' * '' Megalodytes'' (Middle Miocene of California, US) * "cf. ''Megalodytes"'' (Haraichi Middle Miocene of Annaka, Japan) * '' Anserobranta'' (Late Miocene of C Europe) – includes ''"Anas" robusta'', validity doubtful * '' Presbychen'' (Temblor Late Miocene of Sharktooth Hill, US) * '' Afrocygnus'' (Late Miocene – Early Pliocene of EC Africa) * '' Paracygnus'' (Kimball Late Pliocene of Nebraska, US) * '' Eremochen'' (Pliocene) Tadorninae * ''

Australotadorna '' Australotadorna alecwilsoni'' is an extinct genus and species of bird, in the shelduck subfamily of the duck family, from the Late Oligocene of central Australia. The genus name comes from the Latin ''australis'' (“southern” or, derivati ...

'' (Late Oligocene – Early Miocene of Australia) * '' Miotadorna'' (Bathans Early/Middle Miocene of Otago, New Zealand) * Tadorninae gen. et sp. indet. (Calvert Middle Miocene of Maryland, US) * '' Balcanas'' (Early Pliocene of Dorkovo, Bulgaria) – may be synonym of ''Tadorna'' or even

common shelduck The common shelduck (''Tadorna tadorna'') is a waterfowl species of the shelduck genus, ''Tadorna''. It is widespread and common in the Euro-Siberian region of the Palearctic, mainly breeding in temperate and wintering in subtropical regions; in ...

* '' Anabernicula'' (Late Pliocene ? – Late Pleistocene of SW and W North America) * '' Brantadorna'' (Middle Pleistocene of Vallecito Creek, US) * '' Nannonetta'' (Late Pleistocene of Peru) Anatinae * '' Sinanas'' (Middle Miocene) * '' Wasonaka'' (Middle Pliocene) Oxyurinae * '' Pinpanetta'' (Late Oligocene – Early Miocene of Australia) * '' Dunstanetta'' (Bathans Early/Middle Miocene of Otago, New Zealand) – tentatively placed here * '' Tirarinetta'' (Pliocene of Australia) ''

Incertae sedis ' () or ''problematica'' is a term used for a taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertainty ...

'' * ''"Anas" luederitzensis'' (Kalahari Early Miocene of Lüderitzbucht, Namibia) – anatine? * ''

Matanas ''Matanas enrighti'' is an extinct duck from the Miocene of New Zealand. It was described from fossil material (a left humerus) collected from a Saint Bathans Fauna site near Mata Creek, in the lower Bannockburn Formation of the Manuherikia Gr ...

'' (Bathans Early/Middle Miocene of Otago, New Zealand) * Anatidae gen. et sp. indet. MNZ S42797 (Bathans Early/Middle Miocene of Otago, New Zealand) * ''"Oxyura" doksana'' (Early Miocene of Dolnice, Czech Republic) * ''"Aythya" chauvirae'' (Middle Miocene of Sansan, France and Credinţa, Romania) – 2 species * Anatidae gen. et sp. indet. (Middle Miocene of Nördlinger Ries, Germany) – tadornine? * Anatidae gen. et sp. indet. (Sajóvölgyi Middle Miocene of Mátraszõlõs, Hungary) * ''"Anas" meyerii'' (Middle Miocene of Öhningen, Germany) Described from a single badly crushed tarsometatarsus and phalanges. This species was named in 1867 by Milne-Edwards and then recombined in 1964 by Brodkorb to the genus ''

''. This species is currently regarded as Aves ''

incertae sedis ' () or ''problematica'' is a term used for a taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertainty ...

''. * ''"Anas" velox'' (Middle–Late? Miocene of C Europe) – anatine? May include ''"A." meyerii'' * ''"Anas" albae'' (Late Miocene of Polgárdi, Hungary) – mergine? Formerly in ''Mergus'' * ''"Anas" isarensis'' (Late Miocene of Aumeister, Germany) – anatine? * ''"Anser" scaldii'' (Late Miocene of Antwerp, Belgium) – anserine or tadornine * Anatidae gen. et sp. indet. (Waite Late Miocene of Alcoota, Australia) – anatine, oxyurine? * Anatidae gen. et sp. indet. (Waite Late Miocene of Alcoota, Australia) – tadornine? * ''"Anas" eppelsheimensis'' (Early Pliocene of Eppelsheim, Germany) – anatine? * '' Aldabranas'' (Late Pleistocene of Aldabra, Indian Ocean) – anatine or tadornine * ''"Chenopis" nanus'' (Pleistocene of Australia) – at least 2 taxa, may be living species * '' Garganornis'' (Late Miocene of Gargano, Italy) * '' Mioquerquedula'' (Middle Miocene of Mongolia) Putative or disputed prehistoric anatids are: * '' Romainvillia'' (Late Eocene/Early Oligocene) – anseranatid or anatid (own subfamily) * '' Loxornis'' (Deseado Early Oligocene of Argentina) * '' Paracygnopterus'' (Early Oligocene of Belgium and England) * '' Teleornis'' (Deseado Early Oligocene of Argentina) * '' Guguschia'' (Late Oligocene of Pirəkəşkül, Azerbaijan) – anserine or

Pelagornithidae The Pelagornithidae, commonly called pelagornithids, pseudodontorns, bony-toothed birds, false-toothed birds or pseudotooth birds, are a prehistoric family of large seabirds. Their fossil remains have been found all over the world in rocks dati ...

(same as '' Caspiodontornis''?) * '' Chenornis'' (Early Miocene) – anserine or Phalacrocoracidae * '' Paranyroca'' (Rosebud Early Miocene of Bennett County, US) – anatid (own subfamily) or distinct family? * '' Eoneornis'' (Miocene of Argentina) – anatine? A ''

nomen dubium In binomial nomenclature, a ''nomen dubium'' ( Latin for "doubtful name", plural ''nomina dubia'') is a scientific name that is of unknown or doubtful application. Zoology In case of a ''nomen dubium'' it may be impossible to determine whether a ...

'' * '' Eutelornis'' (Miocene of Argentina) – anatine? The Middle Oligocene '' Limicorallus'' (from Chelkar-Teniz (

Kazakhstan Kazakhstan, officially the Republic of Kazakhstan, is a transcontinental country located mainly in Central Asia and partly in Eastern Europe. It borders Russia to the north and west, China to the east, Kyrgyzstan to the southeast, Uzbeki ...

) was sometimes considered an anserine. It is now recognized as a primitive

cormorant Phalacrocoracidae is a family of approximately 40 species of aquatic birds commonly known as cormorants and shags. Several different classifications of the family have been proposed, but in 2021 the IOC adopted a consensus taxonomy of seven ge ...

. The middle Eocene '' Eonessa'' was formerly thought to belong to Anatidae, however reexamination of the holotype in 1978 resulted in the genus being placed as Aves

References

External links

Anatidae videos
on the Internet Bird Collection

– Stamps on ducks, swans and geese {{Taxonbar, from=Q7556 Bird families Waterfowl Extant Rupelian first appearances Taxa named by William Elford Leach