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The common pheasant (''Phasianus colchicus'') is a bird in the pheasant family (Phasianidae). It is native to Asia and has been widely introduced elsewhere as a game bird. In parts of its range, namely in places where none of its relatives occur such as in Europe (where it is naturalized), it is simply known as the "pheasant". Ring-necked pheasant is both the name used for the species as a whole in North America and also the collective name for a number of subspecies and their intergrades which have white neck rings. The word ''pheasant'' is derived from the ancient town of Phasis, the predecessor of the modern port city of Poti in Western Georgia. It is a well-known gamebird, among those of more than regional importance perhaps the most widespread and ancient one in the whole world. The common pheasant is one of the world's most hunted birds;〔 it has been introduced for that purpose to many regions, and is also common on game farms where it is commercially bred. Ring-necked pheasants in particular are commonly bred and were introduced to many parts of the world; the game farm stock, though no distinct breeds have been developed yet, can be considered semi-domesticated. The ring-necked pheasant is the state bird of South Dakota, one of only three U.S. state birds that is not a species native to the United States. The green pheasant (''P. versicolor'') of Japan is sometimes considered a subspecies of the common pheasant. Though the species produce fertile hybrids wherever they coexist, this is simply a typical feature among fowl (Galloanseres), in which postzygotic isolating mechanisms are slight compared to most other birds. The species apparently have somewhat different ecological requirements and at least in its typical habitat, the green pheasant outcompetes the common pheasant. The introduction of the latter to Japan has therefore largely failed. ==Description== There are many colour forms of the male common pheasant, ranging in colour from nearly white to almost black in some melanistic examples. These are due to captive breeding and hybridization between subspecies and with the green pheasant, reinforced by continual releases of stock from varying sources to the wild. For example, the "ring-necked pheasants" common in Europe, North America and Australia do not pertain to any specific taxon, they rather represent a stereotyped hybrid swarm.〔 Body weight can range from , with males averaging and females averaging .〔〔 The adult male common pheasant of the nominate subspecies ''Phasianus colchicus colchicus'' is in length with a long brown streaked black tail, accounting for almost of the total length. The body plumage is barred bright gold and brown plumage with green, purple and white markings. The head is bottle green with a small crest and distinctive red wattle. ''P. c. colchicus'' and some other races lack a white neck ring. The female (hen) is much less showy, with a duller mottled brown plumage all over and measuring long including a tail of around . Juvenile birds have the appearance of the female with a shorter tail until young males begin to grow characteristic bright feathers on the breast, head and back at about 10 weeks after hatching. The green pheasant (''P. versicolor'') is very similar, and hybridization often makes the identity of individual birds difficult to determine. Green pheasant males on average have a shorter tail than the common pheasant and have darker plumage that is uniformly bottle-green on the breast and belly; they always lack a neck ring. Green pheasant females are darker, with many black dots on the breast and belly. In addition, various color mutations are commonly encountered, mainly melanistic (black) and flavistic (isabelline or fawn) specimens. The former are rather common in some areas and are named Tenebrosus pheasant (''P. colchicus'' var. ''tenebrosus''). 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「Common pheasant」の詳細全文を読む スポンサード リンク
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