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The mallard ( or ) or wild duck (''Anas platyrhynchos'') is a dabbling duck which breeds throughout the temperate and subtropical Americas, Europe, Asia, and North Africa, and has been introduced to New Zealand, Australia, Peru, Brazil, Uruguay, Argentina, Chile, the Falkland Islands and South Africa.〔 This duck belongs to the subfamily Anatinae of the waterfowl family Anatidae. The male birds (drakes) have a glossy green head and are grey on wings and belly, while the females (hens or ducks) have mainly brown-speckled plumage. Both sexes have an area of white-bordered black speculum feathers which commonly also include iridescent blue feathers especially among males. Mallards live in wetlands, eat water plants and small animals, and are social animals preferring to congregate in groups or flocks of varying sizes. This species is the ancestor of most breeds of domestic ducks.〔 == Taxonomy and evolution == The mallard was one of the many bird species originally described by Carl Linnaeus in his 18th-century work, ''Systema Naturae'', and still bears its original binomial name.〔 The name ''mallard'' is derived from the Old French ''フランス語:malart'' or ''フランス語:mallart'' "wild drake", although its ultimate derivation is unclear. It may be related to (or at least influenced by) an Old High German masculine proper name ''ドイツ語:Madelhart'', clues lying in the alternate English forms "maudelard" or "mawdelard".〔 ''Masle'' (male) has also been proposed as an influence.〔 Mallards frequently interbreed with their closest relatives in the genus ''Anas'', such as the American black duck, and also with species more distantly related, such as the northern pintail, leading to various hybrids that may be fully fertile.〔 This is quite unusual among such different species, and apparently is because the mallard evolved very rapidly and recently, during the Late Pleistocene. The distinct lineages of this radiation are usually kept separate due to non-overlapping ranges and behavioural cues, but are still not fully genetically incompatible.〔 Mallards and their domesticated conspecifics are also fully interfertile. The genome of ''Anas platyrhynchos'' was sequenced in 2013.〔 Mallards appear to be closer to their Indo-Pacific relatives than to their American ones judging from biogeography. Considering mitochondrial DNA D-loop sequence data, they may have evolved in the general area of Siberia; mallard bones rather abruptly appear in food remains of ancient humans and other deposits of fossil bones in Europe, without a good candidate for a local predecessor species.〔 The large ice age palaeosubspecies which made up at least the European and west Asian populations during the Pleistocene has been named ''Anas platyrhynchos palaeoboschas''. In their mitochondrial DNA, mallards are differentiated between North America and Eurasia,〔 however, in the nuclear genome there is a particular lack of genetic structure.〔 Haplotypes typical of American mallard relatives and spotbills can be found in mallards around the Bering Sea.〔 The Aleutian Islands hold a population of mallards that appear to be evolving towards a subspecies, as gene flow with other populations is very limited.〔 The size of the mallard varies clinally, and birds from Greenland, although larger than birds further south, have smaller bills and are stockier. They are sometimes separated as subspecies, the Greenland mallard (''A. p. conboschas''). 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Mallard」の詳細全文を読む スポンサード リンク
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