Willow Ptarmigan

The Willow Ptarmigan is a circumpolar grouse of the arctic and subarctic that undergoes one of the most dramatic seasonal plumage changes of any bird, molting from pure white in winter (aside from black tail feathers and, in males, a black eye-line) to richly mottled rufous-brown in summer for camouflage against the tundra vegetation. Males in breeding plumage are notably more reddish on the head and neck than females, retaining this coloration into early summer while the rest of the body molts to a more cryptic brown. It is the state bird of Alaska.

Key field marks

• White wings and belly year-round; body plumage changes from white (winter) to mottled rufous-brown (summer)
• Feathered legs and feet year-round, an adaptation to cold and snow
• Male in breeding plumage shows a more extensively chestnut-red head and neck than the female
• Black tail feathers visible in all plumages

Similar species

Rock Ptarmigan is very similar but slightly smaller, grayer in summer plumage, and males show a black eye-line ("mask") in spring that Willow Ptarmigan lacks; Rock Ptarmigan also favors higher, more barren, rocky terrain than the willow-scrub habitat preferred by Willow Ptarmigan. White-tailed Ptarmigan is smaller with an all-white tail in every season.

Habitat and Range

Willow Ptarmigan favor lower-elevation arctic and subarctic tundra with willow and birch scrub, wetter and shrubbier habitat than the more barren terrain used by Rock Ptarmigan.

Range

The species has a circumpolar distribution across the arctic and subarctic regions of Alaska, Canada, Scandinavia, and Russia, generally at lower elevations and latitudes than Rock Ptarmigan within the same regions.

Migration

Most populations are largely resident or make only short-distance movements to lower, more sheltered wintering areas with accessible willow shrubs, though some far-northern populations move farther south in severe winters.

Behavior

Willow Ptarmigan are well camouflaged and generally rely on stillness to avoid detection, forming small flocks (coveys) especially in winter.

Voice

Males give a loud, raucous, laughing call often rendered as "go-BACK, go-BACK, go-BACK," typically delivered during a short display flight.

Feeding

Willow buds, catkins, and leaves make up the bulk of the winter diet, supplemented by berries in fall and insects, especially important for growing chicks in summer.

Nesting and breeding

Unlike most grouse, Willow Ptarmigan form monogamous pairs, and the male often remains near the nest and may help defend the female and brood, an unusual level of male parental involvement among gamebirds.