The diving ducks, commonly called pochards or scaups, are a category of

duck Duck is the common name for numerous species of waterfowl in the family Anatidae. Ducks are generally smaller and shorter-necked than swans and geese, which are members of the same family. Divided among several subfamilies, they are a fo ...

which feed by diving beneath the surface of the water. They are part of

Anatidae The Anatidae are the biological family of water birds that includes ducks, geese, and swans. The family has a cosmopolitan distribution, occurring on all the world's continents except Antarctica. These birds are adapted for swimming, floating ...

, the diverse and very large

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

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 she ...

, and

swan Swans are birds of the family Anatidae within the genus ''Cygnus''. The swans' closest relatives include the geese and ducks. Swans are grouped with the closely related geese in the subfamily Anserinae where they form the tribe Cygnini. Sometim ...

s. The diving ducks are placed in a distinct tribe in the subfamily

Anatinae The Anatinae are a subfamily of the family Anatidae (swans, geese and ducks). Its surviving members are the dabbling ducks, which feed mainly at the surface rather than by diving. The other members of the Anatinae are the extinct moa-nalo, a yo ...

, the Aythyini. While morphologically close to the

dabbling duck The Anatinae are a subfamily of the family Anatidae (swans, geese and ducks). Its surviving members are the dabbling ducks, which feed mainly at the surface rather than by diving. The other members of the Anatinae are the extinct moa-nalo, a yo ...

s, there are nonetheless some pronounced differences such as in the structure of the

trachea The trachea, also known as the windpipe, is a cartilaginous tube that connects the larynx to the bronchi of the lungs, allowing the passage of air, and so is present in almost all air-breathing animals with lungs. The trachea extends from th ...

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

cytochrome ''b'' and

NADH dehydrogenase NADH dehydrogenase is an enzyme that converts nicotinamide adenine dinucleotide (NAD) from its reduced form (NADH) to its oxidized form (NAD+). Members of the NADH dehydrogenase family and analogues are commonly systematically named using the for ...

subunit 2

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 called ...

data indicate that the dabbling and diving ducks are fairly distant from each other, the outward similarities being due to

convergent evolution Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last com ...

. Alternatively, the diving ducks are placed as a subfamily Aythyinae in a subfamily Anatidae which would encompass all duck-like birds except the whistling-ducks. The

seaduck 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 sp ...

s commonly found in coastal areas, such as the

long-tailed duck 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 t ...

(formerly known in the U.S. as oldsquaw),

scoter 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 ...

goldeneye ''GoldenEye'' is a 1995 spy film, the seventeenth in the List of James Bond films, ''James Bond'' series produced by Eon Productions, and the first to star Pierce Brosnan as the fictional Secret Intelligence Service, MI6 agent James Bond (lit ...

merganser ''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 (''M ...

bufflehead The bufflehead (''Bucephala albeola'') is a small sea duck of the genus ''Bucephala'', the goldeneyes. This species was first described by Carl Linnaeus in his landmark 1758 10th edition of ''Systema Naturae'' as ''Anas albeola''. The genus n ...

and

eider 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 qu ...

s, are also sometimes colloquially referred to in North America as diving ducks because they also feed by diving; their subfamily (Merginae) is a very distinct one however. Although the group is cosmopolitan, most members are native to the Northern Hemisphere, and it includes several of the most familiar Northern Hemisphere ducks. This group of ducks is so named because its members feed mainly by diving, although in fact the ''Netta'' species are reluctant to dive, and feed more like dabbling ducks. These are gregarious ducks, mainly found on fresh water or on

estuaries An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environme ...

, though the

greater scaup The greater scaup (''Aythya marila''), just scaup in Europe or, colloquially, "bluebill" in North America, is a mid-sized diving duck, larger than the closely related lesser scaup. It spends the summer months breeding in Alaska, northern Canad ...

becomes marine during the northern winter. They are strong fliers; their broad, blunt-tipped wings require faster wing-beats than those of many ducks and they take off with some difficulty. Northern species tend to be migratory; southern species do not migrate though the

hardhead The hardhead (''Aythya australis''), also known as the white-eyed duck, is the only true diving duck found in Australia. The common name "hardhead" has nothing to do with the density of the bird's skull, instead referring to the difficulty enco ...

travels long distances on an irregular basis in response to rainfall. Diving ducks do not walk as well on land as the

s; their legs tend to be placed further back on their bodies to help propel them when underwater.

Systematics

Three

genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial ...

are included in the Aythyini. The marbled duck which makes up the

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

genus ''Marmaronetta'', however, seems very distinct and might have diverged prior to the split of dabbling and diving ducks as indicated by morphological and molecular characteristics. 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 ...

, previously treated separately in ''Rhodonessa'', has been suggested to belong into ''Netta'', but this approach has been questioned.

DNA sequence DNA sequencing is the process of determining the nucleic acid sequence – the order of nucleotides in DNA. It includes any method or technology that is used to determine the order of the four bases: adenine, guanine, cytosine, and thymine. Th ...

analyses have found it to be the earliest diverging member of the pochard group. The molecular analysis also suggests that the white-winged duck should be placed into a

genus ''Asarcornis'' which is fairly close to ''Aythya'' and might belong into this subfamily. Aythya australis female - Hurstville Golf Course

Family Anatidae

* Subfamily Anatinae ** Tribe Aythyini *** Genus ''Rhodonessa'' ****

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 ...

(''Rhodonessa caryophyllacea'') ; probably extinct (1945?) ***Genus '' Marmaronetta'' **** Marbled duck (''Marmaronetta angustirostris'') ***Genus '' Netta'' (provisionally including ''Rhodonessa'') **** Red-crested pochard (''Netta rufina'') **** Southern pochard (''Netta erythrophthalma'') **** Rosy-billed pochard (''Netta peposaca'') *** Genus ''

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 M ...

'' ****

Canvasback The canvasback (''Aythya valisineria'') is a species of diving duck, the largest found in North America. Taxonomy Scottish-American naturalist Alexander Wilson described the canvasback in 1814. The genus name is derived from Greek ''aithuia'' ...

(''Aythya valisineria'') ****

Common pochard The common pochard (; ''Aythya ferina'') is a medium-sized diving duck. The scientific name is derived from Greek '' aithuia'', an unidentified seabird mentioned by authors including Hesychius and Aristotle, and Latin ''ferina'', "wild gam ...

(''Aythya ferina'') **** Redhead (''Aythya americana'') ****

Ring-necked duck The ring-necked duck (''Aythya collaris'') is a diving duck from North America commonly found in freshwater ponds and lakes. The scientific name is derived from Greek , an unidentified seabird mentioned by authors including Hesychius and Aris ...

(''Aythya collaris'') ****

Hardhead The hardhead (''Aythya australis''), also known as the white-eyed duck, is the only true diving duck found in Australia. The common name "hardhead" has nothing to do with the density of the bird's skull, instead referring to the difficulty enco ...

(''Aythya australis'') ****

Baer's pochard Baer's pochard (''Aythya baeri'') is a diving duck found in eastern Asia. It is a resident bird in North and Central China, formerly bred in southeast Russia and Northeast China, migrating in winter to southern China, Vietnam, Japan, and India. ...

(''Aythya baeri'') **** Ferruginous duck (''Aythya nyroca'') ****

Madagascar pochard The Madagascar pochard or Madagascan pochard (''Aythya innotata''; mg, Fotsy maso, Onjo) is an extremely rare diving duck of the genus ''Aythya''. Thought to be extinct in the late 1990s, specimens of the species were rediscovered at Lake Matsa ...

(''Aythya innotata'') – feared to be extinct, rediscovered (2006) ****Réunion pochard, (''Aythya'' cf. ''innotata'') – extinct (c. 1690s) **** New Zealand scaup (''Aythya novaeseelandiae'') ****

Tufted duck The tufted duck or tufted pochard (''Aythya fuligula'') is a small diving duck with a population of close to one million birds, found in northern Eurasia. The scientific name is derived from Ancient Greek '' aithuia'', an unidentified seabird men ...

(''Aythya fuligula'') ****

Greater scaup The greater scaup (''Aythya marila''), just scaup in Europe or, colloquially, "bluebill" in North America, is a mid-sized diving duck, larger than the closely related lesser scaup. It spends the summer months breeding in Alaska, northern Canad ...

(''Aythya marila'') ****

Lesser scaup The lesser scaup (''Aythya affinis'') is a small North American diving duck that migrates south as far as Central America in winter. It is colloquially known as the little bluebill or broadbill because of its distinctive blue bill. The origin o ...

(''Aythya affinis'')

References

{{DEFAULTSORT:Diving Duck Aythyinae Diving ducks Articles containing video clips