The Common Pheasant originated in the Caucasus. The genus name
"Phasianus" and the species name "colchicus" relate to Georgian place names.
The cock pheasant has a beautiful iridescent blue-green-purple head, neck and chest and a scarlet, heart-shaped wattle. The female is a plainer light brown.
The nominate (Caucasian) subspecies of Common Pheasant has NO WHITE NECK COLLAR. The one above has a slight patch of collar on the left, indicating it is not pure-bred.
Mongolian and Chinese subspecies have white neck collars, the former with a dark rump and the latter with a light rump. The common European/American Ring-necked Pheasant, which generally has a three-quarter, white collar, is a stable hybrid population of various subspecies of Common Pheasant (and possibly also the Japanese Green Pheasant) imported/bred for hunting.
The rump is ginger. The tail of the male is longer than his body.
A Ring-necked version -- this one with bluish neck and also with a white-fringed skull cap.
The hen is a plain brown, similar to the hen Ring-necked.
Like the Ring-necked hen, there are white and fawn versions.