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.