Overview: Chris Packham and Michaela Strachan broadcast live from the Scottish Highlands, reporting on the overnight wildlife action. Martin Hughes-Games scales the snowy Cairngorms to track down the mountain hare and understand how this mammal has adapted to the near Arctic conditions. Meanwhile, the team reveal the secrets behind an enormous roost of rooks, one of the UK's biggest winter spectacles. And Gordon Buchanan braves our coastal waters to investigate marine creatures in winter.