Rock Ptarmigan

The Rock Ptarmigan is a circumpolar grouse closely related to the Willow Ptarmigan but generally found on higher, more barren, rocky ground with sparser vegetation. Like its relative, it undergoes a dramatic seasonal plumage change from pure white in winter to mottled gray-brown in summer, but is overall grayer and finer-patterned than the more rufous Willow Ptarmigan. In spring, males develop a distinctive black line through the eye that is a useful field mark not shown by Willow Ptarmigan.

Key field marks

• White plumage in winter (with black tail); grayer, finely mottled gray-brown plumage in summer (less rufous than Willow Ptarmigan)
• Breeding male shows a black eye-line/mask in spring
• Slightly smaller and more slender-billed than Willow Ptarmigan
• Feathered legs and feet year-round

Similar species

Willow Ptarmigan is larger, more rufous overall in summer, favors lower shrubby willow habitat, and males lack the black eye-line. White-tailed Ptarmigan is smaller, found farther south in alpine habitat, and has an all-white tail in every plumage.

Habitat and Range

Rock Ptarmigan favor high, barren, rocky tundra and alpine slopes with sparse vegetation, typically at higher elevations or more exposed sites than the shrubbier habitat used by Willow Ptarmigan.

Range

The species has a circumpolar arctic and alpine distribution across northern Canada, Alaska, Greenland, Scandinavia, and Russia, generally overlapping with Willow Ptarmigan but occupying more barren terrain within the same regions.

Migration

Most populations are resident or make only short local movements to lower, more sheltered slopes in severe winter weather.

Behavior

Rock Ptarmigan rely heavily on camouflage and stillness in the sparse, exposed terrain they inhabit, forming small flocks outside the breeding season.

Voice

Males give a harsh, croaking, belching-like call during display flights, distinct from the laughing call of the Willow Ptarmigan.

Feeding

Diet consists of buds, leaves, seeds, and berries of tundra plants, shifting seasonally as different foods become available.

Nesting and breeding

Pairs are generally monogamous for the season; the female nests on the ground in a shallow scrape among rocks or low vegetation, and males may help guard the nest area during incubation.