Ptarmigans are possibly Britain's toughest birds and live in the cold, harsh mountains of Scotland.
In snowy conditions, their feathered feet act as snow shoes, so the ptarmigan can walk even on soft snow.
Ptarmigans are masters of camouflage, changing their colour to suit the season.
In winter, they are completely white except for a short black tail,
while in summer a brown and yellow plumage blends the ptarmigan into the lichen covered rocks.