White-tailed Ptarmigan

Overview

The White-tailed Ptarmigan is the smallest of the three ptarmigan species and the only one restricted to North America, occupying high alpine tundra above treeline in mountain ranges from Alaska south through the Rockies. It shares the seasonal white-to-brown molt of its relatives but is unique among ptarmigan in retaining a white tail in every season.

Feather Identification

• Tail feathers: pure white year-round, the single most diagnostic feature separating this species from Rock and Willow Ptarmigan, both of which have black tails
• Summer body feathers: finely mottled gray-brown, matching rocky alpine tundra substrate
• Winter body feathers: entirely white, blending with snow cover
• Size: the smallest of the ptarmigan, with correspondingly smaller and more delicate feathers
• Vs. Rock/Willow Ptarmigan: the combination of small size and an all-white tail is unmistakable once a tail feather is available for comparison

Plumage Notes

Both sexes show the same mottled gray-brown summer plumage transitioning to pure white in winter, with the tail remaining white in all plumages, unlike the black-tailed Rock and Willow Ptarmigan. Juveniles resemble a duller version of the summer adult. The species undergoes the same multi-stage seasonal molt pattern characteristic of ptarmigan.

Habitat & Range

White-tailed Ptarmigan are restricted to high alpine tundra above treeline in mountain ranges of western North America, from Alaska and the Yukon south through the Rocky Mountains. They are non-migratory, typically moving only short distances downslope to more sheltered terrain during severe winter weather.

Behavior & Field Notes

Males establish alpine territories in spring, giving soft clucking and cackling calls during courtship. Diet consists of alpine plant buds, leaves, and berries in summer, shifting to willow and other woody buds in winter. Nests are shallow scrapes concealed among alpine rocks and vegetation. The species is extremely well camouflaged and often remains motionless at close range before flushing.