By Tina Mitchell You have to know that a bird loves cold if it willingly migrates to South Park for the winter. Of all of the hawks in the Buteo genus, only the Rough-legged Hawk is so thoroughly linked with cold climates. In North America, Rough-legged Hawks breed primarily on the tundra of the Arctic and winter in open country of southern Canada and the northern United States. Driving U.S. Hwy. 285 through South Park during the cold season, you will likely find them perched on power poles or fence posts, surveying the snowy fields. Ah, just like summer in…