Tweet of the Day is a series of fascinating stories about the British birds inspired by their calls and songs.

Wildlife Sound Recordist, Chris Watson, presents the Eider. Eiders are northern sea-ducks perhaps most famous for the soft breast feathers with which they line their nests. These feathers were collected by eider farmers and used to fill pillows and traditional 'eider -downs'. Drake eiders display to the females with odd moaning calls which you can hear in the programme.