The ptarmigan is one of four types of grouse to be found in Scotland, and its plumage changes from grey and brown to a brilliant white to reflect its winter habitat.
But it is not just the ptarmigan who adapts to the changing climate in this way. The mountain hare is another animal that sheds its autumnal brown fur to reveal a white coat when winter comes to the hills.
The Highlands and the Cairngorms in particular, are where reindeer can be spotted who start to shed their antlers during winter, and in the forests and glens the courting season begins for both red squirrels and wildcats. On still nights the very distinctive screeching mating call of the wildcat can often be heard.
Winter is also the time when thousands of white-front and barnacle geese land on the island of Islay, off the west coast of Scotland. The Loch Gruinart nature reserve is an ideal spot to witness these wonderful birds as they arrive from Greenland. On the mainland, a variety of geese, swans and ducks can also be found around Spey Bay in the Highlands, the Montrose Basin in Dundee and Angus and around the Solway Firth in Dumfries & Galloway.