The Rock Ptarmigan is closely related to the slightly larger Willow Ptarmigan, and occupies the same natural range in the Arctic and subarctic regions of Eurasia and North America. However the two species occupy different habitats, the Rock Ptarmigan prefers more rocky and barren environments at higher elevation. As other species of ptarmigans, the Rock Ptarmigan changes throughout the year in a multi-step molting process. Males gradually change between a white winter plumage, a conspicuous breeding plumage and a cryptic plumage in a continuous cycle.
