Eiders are large seaducks in the genus Somateria. The Steller's Eider, despite its name, is in a different genus.
The three extant species all breed in the cooler latitudes of the Northern hemisphere.
- Common Eider Somateria mollissima
- Spectacled Eider Somateria fischeri
- King Eider Somateria spectabilis
- Hybrid Eider
- Spectacled Eider
Two undescribed species are known from fossils, one from Middle Oligocene rocks in Kazakhstan and another from the Late Miocene or Early Pliocene of Lee Creek Mine, USA. The former may not actually belong into this genus.