In the UK, the Common Scoter is recognised as a
nationally threatened species (the only species of waterfowl to be
red-listed) because of its small and declining breeding population.
There are only 200 pairs in Great Britain and Ireland (90 in
Scotland, 110 in Ireland) and the species is now extinct as a
breeding species in Northern Ireland (there were 150 pairs in
1967). Numbers in the Flow country of northeast Scotland have
declined from 55 pairs in 1988 to only 28 in 1996. Eutrophication
and afforestation of breeding sites, fish stocking leading to
increased competition with scoters for invertebrate food, and
predation by introduced mink have all been suggested as factors
responsible for these declines, while wintering populations are
threatened by oil pollution and over-harvesting of shellfish. The
Sea Empress oil spill in South Wales in February 1996 killed over
5000 Common Scoter.
