eider
/ˈʌɪdə
/(also eider duck) 
noun (plural same or eiders)
A northern sea duck, of which the male is mainly black-and-white with a coloured head, and the female brown.
- Genus Somateria (and Polysticta), family Anatidae: four species.
- Both of these types are plentiful on the Cape, as are sea ducks, such as scoters and eiders, viewable from many vantage points.
- They frequently nest in colonies, often in association with eiders.
Origin
Late 17th century: from Icelandic æthur, from Old Norse æthr.