Common pheasant
Taxonomy and systematics

This species was first scientifically described by Carl Linnaeus in his landmark 1758 10th edition of Systema Naturae under its current scientific name. The common pheasant is distinct enough from any other species known to Linnaeus for a laconic rufus, capîte caeruleo – "a red pheasant with blue head" – to serve as entirely sufficient description. Moreover, the bird had been extensively discussed before Linnaeus established binomial nomenclature. His sources are the Ornithologia of Ulisse Aldrovandi, Giovanni Pietro Olina 's Uccelliera, John Ray 's Synopsis methodica Avium & Piscium, and A Natural History of the Birds by Eleazar Albin. Therein—essentially the bulk of the ornithology textbooks of his day—the species is simply named "the pheasant" in the books' respective languages. Whereas in other species, such as the eastern meadowlark (Sturnella magna), Linnaeus felt it warranted to cite plumage details from his sources, in the common pheasant's case he simply referred to the reason of the bird's fame: principum mensis dicatur. The type locality is given simply as "Africa, Asia".

However, the bird does not occur in Africa, except perhaps in Linnaeus's time in Mediterranean coastal areas where they might have been introduced during the Roman Empire. The type locality was later fixed to the Rioni River in western Georgia – known as Phasis to the Ancient Greeks. These birds, until the modern era, constituted the bulk of the introduced stock in parts of Europe that was not already present; the birds described by Linnaeus's sources, though typically belonging to such early introductions, would certainly have more alleles in common with the transcaucasian population than with others. The scientific name is Latin for "pheasant from Colchis ", colchicus referring to the west of modern-day Georgia; the Ancient Greek term corresponding to the English "pheasant" is Phasianos ornis (Φασιανὸς ὂρνις), "bird of the river Phasis". Although Linnaeus included many Galliformes in his genus Phasianius —such as the domestic chicken and its wild ancestor the red junglefowl, nowadays Gallus gallus —today only the common and the green pheasant are placed in this genus. As the latter was not known to Linnaeus in 1758, the common pheasant is naturally the type species of Phasianus.

In the US, common pheasants are widely known as "ring-necked pheasants". More colloquial North American names include "chinks" or, in Montana, "phezzens". In China, meanwhile, the species is properly called zhi ji (雉鸡)—"pheasant-fowl"—essentially implying the same as the English name "common pheasant". Like elsewhere, P. colchicus is such a familiar bird in China that it is usually just referred to as shan ji (山雞), "mountain chicken", a Chinese term for pheasants in general.

As of 2005, it had the smallest known genome of all living amniotes, only 0.97 pg (970 million base pairs), roughly one-third of the human genome's size; however, the black-chinned hummingbird is now currently held to have the smallest.
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