The eider is the UK's largest sea duck and one of the most distinctive coastal birds. Found mainly on Scottish coasts, its welfare depends on mollusc-rich coastal habitats and freedom from disturbance during breeding.
Eider welfare at breeding colonies is sensitive to human disturbance. Females incubating nests tolerate close approach — their well-known tameness at places like Farne Islands means birdwatchers can observe at close range. However, systematic disturbance of whole colonies causes nest abandonment and chick mortality. Dog disturbance is the most significant welfare threat at accessible breeding beaches. Wintering eiders on Scottish coasts face welfare risks from oil spills and gill net entanglement. The species' dependence on blue mussels makes it vulnerable to climate-driven changes in mussel availability — warming seas affect mussel distribution and condition quality.