The ruffed grouse (Bonasa umbellus) is a medium-sized grouse occurring in forests from the Appalachian Mountains across Canada to Alaska. It is the most widely distributed game bird in North America. It is non-migratory. It is the only species in the genus Bonasa. The ruffed grouse is sometimes incorrectly referred to as a 'partridge', an unrelated phasianid, and occasionally confused with the grey partridge, a bird of open areas rather than woodlands. The ruffed grouse is the state game bird of Pennsylvania, United States. The average life span of a ruffed grouse is one year, although some birds are thought to live for as long as eleven years. Ruffed grouse are polygynous, and males may mate with several females during the breeding season.[citation needed] (Source: Wikipedia.org, CC BY-SA)