Female ptarmigan (Lagopus mutus) in summer plumage, Iceland, Polar Regions

An adult female willow ptarmigan (Lagopus lagopus) in the shrubs in Denali National Park, Alaska, United States of America, North America

An adult female willow ptarmigan (Lagopus lagopus) in summer plumage on the Snaefellsnes Peninsula, Iceland, Polar Regions

Female willow ptarmigan (Lagopus lagopus), Denali National Park and Preserve, Alaska, United States of America, North America

Female ptarmigan (Lagopus mutus), moulting from winter plumage in April, Cairngorm, Scotland, United Kingdom, Europe

Ptarmigan (Lagopus mutus) female sitting hidden in long grass, in summer and winter plumage. Highlands, Scotland, UK

A female ptarmigan on the tundra near Camp Victor, west Greenland, Polar Regions

A female ptarmigan on a nest on the Greenland tundra near Camp Victor, west Greenland, Polar Regions

Ptarmigan (Lagopus mutus) female sitting hidden in long grass, in summer and winter plumage. Highlands, Scotland, UK

Ptarmigan (Lagopus mutus) female sitting hidden in long grass, in summer and winter plumage. Highlands, Scotland, UK

A female ptarmigan with young on the Greenland tundra near Camp Victor, west Greenland, Polar Regions

Ptarmigan (Lagopus mutus) female standing on snow in winter and summer plumage. Highlands, Scotland, UK

Ptarmigan (Lagopus mutus) female sitting hidden in long grass, in summer and winter plumage, blue sky in background. Highlands, Scotland, UK

A female ptarmigan on a nest on the Greenland tundra near Camp Victor, west Greenland, Polar Regions

Rock ptarmigan;Lagopus muta) on a rock at the top of a mountain, Alps, Austria.