Eider Duck Welfare on Northern Coasts

The eider is a large sea duck breeding on northern coasts that has declined significantly in Scotland, with welfare linked to food availability and avian influenza.

Key Facts

UK eider breeding population has declined by 50 percent since the late 1990s
Breeds colonially on islands and coastal headlands, females lining nests with breast down
Females lose 40 percent of body weight during incubation as they rarely leave the nest
Diet consists almost entirely of mussels and other bivalves obtained by diving
Avian influenza H5N1 caused significant mortality in eider colonies from 2022 onwards

Welfare Considerations

Eider welfare on breeding grounds is severely challenged by recent H5N1 avian influenza outbreaks. Mass mortality events in established colonies have reduced populations that had already declined due to food availability changes. Mussel and bivalve prey availability in inshore waters has been affected by warming sea temperatures that alter shellfish distribution. Human disturbance of nesting colonies causes females to abandon nests during the critical incubation period when they are already physiologically stressed from the energetic demands of fasting. Mink predation of eggs and chicks is a significant welfare pressure on island colonies. Controlling mink, managing disturbance, and monitoring colonies for disease are the primary welfare interventions available.

What You Can Do

Support Scottish Eider Survey monitoring programs that track population changes
Keep dogs and people away from eider nesting colonies during May to July
Advocate for mink control programs on islands with eider breeding colonies
Back avian influenza surveillance and monitoring programs for seabird colonies