Tonight's theme is 'sounds of the season'. Plus Nick Baker takes a closer look at winter down the lens. He will be dissecting galls and examining a range of mystery objects sent in by viewers. Also including backstage moments from behind the scenes of Winterwatch.

Tonight, Nick Baker is chasing snow fleas and investigating mysterious blobs in the countryside. Soundman Gary Moore is talking winter birdsong and Euan McIlwraith is there with a roundup of what's been appearing on the Winterwatch cameras all week.