The first part of a landmark new series about the wildlife of the Scottish Highlands, narrated by Ewan McGregor. It's late March in the Cairngorm mountains and the hills are on fire! Old heather is being burned in readiness for the grouse season. Traditionally, this inferno marks the end of winter and the start of spring in this wilderness. But spring is the most unpredictable of all seasons here. Ospreys, red squirrels, dippers, capercaillies, roe deer and bottlenose dolphins have struggled to find food and raise their young while coping with the extremes of wind and weather.

The second part of the landmark series about the wildlife of the Scottish Highlands narrated by Ewan McGregor. Summer is the most intense of all the seasons in the Highlands. Animals are in a great race to raise their young to independence before the nights close in and the storms of autumn arrive. Some, like otters and pine martens, are single mothers working ceaselessly for their young, while others, including golden eagles, work in pairs to look after the chicks. Most spectacularly of all, young guillemots on dramatic Handa face a leap for life as they tumble to the sea from 400ft cliffs.

The third part of the Highland wildlife saga narrated by Ewan McGregor. It's a still, clear autumn day in Glen Affric in the north west Highlands. The forests are flushed with gold, but it's a shallow beauty that marks the beginning of the Highlands' longest, darkest and most overwhelming season. Animals that can't migrate to milder climes have to be equipped to deal with an all-out assault from the weather. Reindeer, ptarmigan and mountain hare are all adapted for these arctic-like conditions, but this turns out to be one of the snowiest winters in living memory, driving the animals of the Highlands to the absolute limit.

The final part of the landmark wildlife series narrated by Ewan McGregor. The Highlands may appear a wild and unforgiving place, but for millennia people have lived alongside wild animals here, sharing the same weather, seasons and landscapes. For many years, the impact of humans on the landscape has been damaging, with forests cut down, seas warming and many iconic species like the wolf and bear vanishing. But now things are changing and people are working to put back what we've lost. Humans are finding ways of protecting the Highlands' precious ospreys, eagles, red kites, seabirds and dolphins. Never before has so much work been done to restore the wild Highlands to its full glory.