Eiderdown quilts and pillows used to be very common, but now have been mostly replaced by synthetic materials. The eiderdown is harvested from the linings of the eider’s nests, after the young ducks have left the nest. Originally, the ‘down’ is plucked, by the adult ducks, from the female’s breast. This creates a very warm and soft lining for the young ducks.
As can be seen from the photos, eider ducks are very gregarious birds.