Cairngorms

The programme heads to the Cairngorms, where Joe Crowley is at Britain's largest national nature reserve, Mar Lodge. He is on the search for ptarmigan at the top of one of the tallest mountains in Britain. Helen Skelton meets one of Scotland's most extraordinary creatures - the golden eagle. And Adam Henson is already preparing for next year's new arrivals on his farm. Tom Heap is looking at Britain's favourite meat, chicken, and finding out what goes into supplying almost one billion chickens a year.