Eider Duck
Somateria mollissima
The common eider, also called St. Cuthbert's duck or Cuddy's duck, is a large sea-duck that is distributed over the northern coasts of Europe, North America and eastern Siberia.
Photo: Wikimedia Commons (CC) via https://en.wikipedia.org/wiki/Common_eider
Taxonomy & Classification
Kingdom
Animalia
Phylum
Chordata
Class
Aves
Order
Anseriformes
Family
Anatidae
Genus
Somateria
Eider Duck belongs to the family Anatidae, order Anseriformes, within the Aves class.
Species Profile
The common eider, also called St. Cuthbert's duck or Cuddy's duck, is a large sea-duck that is distributed over the northern coasts of Europe, North America and eastern Siberia. It breeds in Arctic and some northern temperate regions, but winters somewhat farther south in temperate zones, when it can form large flocks on coastal waters. It can fly at speeds up to 113 km/h (70 mph).
Common Eider populations are declining primarily due to climate change impacts on Arctic breeding grounds, including altered sea ice patterns and changing food availability. Hunting pressure, oil spills, and coastal development further threaten populations, while avian influenza outbreaks have caused significant mortality events in recent years.
Key Facts
Habitat & Distribution
This species dives for crustaceans and molluscs, with mussels being a favoured food. The eider will eat mussels by swallowing them whole; the shells are then crushed in their gizzard and excreted. When eating a crab, the eider will remove all of its claws and legs, and then eat the body in a similar fashion. It is abundant, with populations of about 1.5–2 million birds in both North America and...
Threats
IUCN Red List: Endangered
Common Eider populations are declining primarily due to climate change impacts on Arctic breeding grounds, including altered sea ice patterns and changing food availability. Hunting pressure, oil spills, and coastal development further threaten populations, while avian influenza outbreaks have caused significant mortality events in recent years.
Avian influenza outbreaks
Climate change and sea ice loss
Hunting and egg collection
Oil spills and marine pollution
Coastal development and habitat loss
National vs Global Threat Status
How this species is assessed at the national level compared to its IUCN global status (EN).
| Country | National Status | Global Status | Comparison |
|---|---|---|---|
| EU | ENEndangered | ENEndangered | Same |
| EU | ENEndangered | ENEndangered | Same |
National Red List data sourced from the National Red List Project (nationalredlist.org, ZSL) and country-specific Red List authorities.
Community Sightings
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Sources & Attribution
How to Cite
IUCN: IUCN (2025). The IUCN Red List of Threatened Species. Version 2025-1. Available at: https://www.iucnredlist.org. doi:10.2305/IUCN.UK.2025-1.RLTS
GBIF: GBIF.org (2025). GBIF Home Page. Available at: https://www.gbif.org
National Red Lists: ZSL (2025). National Red List. Zoological Society of London. Available at: https://www.nationalredlist.org
This page: SpeciesRadar (2025). Eider Duck (Somateria mollissima). SpeciesRadar: Intelligence for Earth's Biodiversity. Available at: https://speciesradar.org/species/eider-duck