Rock ptarmigan

Lore & Background

The rock ptarmigan is 34–36 cm long with an 8 cm tail, a wingspan of 54–60 cm, and a weight of 440–640 g. It is about ten percent smaller than the willow ptarmigan.

Its plumage moults from white in winter to grey and brown in spring or summer, providing camouflage that matches the seasons. The breeding male has greyish upper parts with white wings and underparts; in winter, it becomes completely white except for black outer tail feathers and an eye line. It can be distinguished from the winter willow ptarmigan by its preference for higher elevations and more barren habitats, as well as its slender bill; males additionally have black lores, absent in the willow ptarmigan, though also absent in female rock ptarmigan.

The genus name Lagopus is derived from Ancient Greek for 'hare' and 'foot', referring to the bird's feathered legs. The species name muta comes from Neo-Latin and means 'mute', referring to the simple croaking song of the male. It was for a long time misspelt mutus. The word ptarmigan comes from the Gaelic tarmachan, meaning croaker; the p- was added due to a mistaken belief in a Greek origin.

The rock ptarmigan has 23 accepted subspecies, ranging from the Aleutian Islands and Alaska across the Arctic to Greenland, Iceland, Svalbard, Scotland, the Alps, the Pyrenees, Siberia, Mongolia, and Japan. It is a sedentary species that breeds across Arctic and Subarctic Eurasia and North America on rocky mountainsides and tundra. It is widespread in the Arctic Cordillera and across the Eurasian Arctic from Norway east to the Siberian Far East, with isolated populations in the mountains of Scotland, the Pyrenees, the Alps, Bulgaria, the Urals, the Pamir Mountains, the Altay Mountains, and Japan, where it occurs only in the Japanese Alps and on Mount Haku.

Reader's Guide

The rock ptarmigan is notable for its extensive geographic range and numerous subspecies, reflecting adaptation to diverse Arctic and alpine environments. Its seasonal camouflage—white in winter, grey and brown in spring and summer—is a classic example of cryptic coloration. The species is largely sedentary, though northern populations show more dispersive movement; birds have been found in Iceland in winter with Greenland-origin minerals in their gizzards, having crossed the Denmark Strait, and a bird ringed on Disko Island off west Greenland was recovered further south in Qaqortoq the following winter. It has been introduced to New Zealand, South Georgia, the Kerguelen Islands, and the Crozet Islands; attempted introductions to the Faroe Islands and Ireland failed.

Male rock ptarmigans emit guttural snores and rattles, often directed to other males during breeding season. Aerial courtship rituals involve fast forward flight with rapidly-beating wings followed by an upward glide, tail fanned out, accompanied by a rasping call described as a stick pulled rapidly across the slats of a picket fence. On the ground, males defend space by calling and chasing other males; physical conflicts between territorial males rarely occur.

The male's red eye comb has been the focus of studies regarding sexual selection; in a population in Scarpa Lake, Nunavut, mating success among males during the first year was influenced by comb size and condition, and bigamous males had larger combs than monogamous males. The correlation to size disappeared after the first year, but the correlation to comb condition remained. The rock ptarmigan becomes sexually mature at six months and commonly has up to six chicks, a high breeding rate that makes population size little affected by factors such as hunting.