The Caledonian pine forest at Abernethy, Rothiemurchus and Glenmore is the heart of it. Capercaillie — a turkey-sized grouse now perilously close to extinction in Britain — survives here, along with crested tit, Scottish crossbill (Britain's only endemic bird species) and red squirrel, which are common at forest feeding stations.

The Loch Garten and Insh Marshes reserves hold ospreys through the summer, with nest cameras and hides, plus goldeneye, and in winter geese and whooper swans on the marshes.

The moorland and glens hold red deer in large numbers, mountain hare turning white in winter, and raptors — golden eagle, and the hen harriers whose persecution on grouse moors remains a live and bitter issue in Scotland.

The plateau above 1,000 metres is Arctic in character and holds ptarmigan, dotterel and snow bunting, along with the reindeer herd introduced to the Cairngorm slopes, which can be visited on guided hill walks.

The rivers hold otter, dipper and, in autumn, salmon running upstream.

Spring brings displaying birds and long days; autumn brings the deer rut and colour; winter turns the plateau genuinely dangerous but delivers mountain hares in white and the best chance of snow.

Practicalities

Aviemore is the main base, on the train line from Edinburgh and Inverness. A car helps for the outlying reserves.

Capercaillie are so threatened that some forests ask visitors to keep to paths and avoid certain areas in spring — and lek viewing is generally discouraged. Respect the signage; disturbance is one of the pressures driving the decline. Plateau weather kills people every year: it is Arctic ground, and it needs to be treated that way.