European seaducks

Seaducks are those ducks that spend the majority of the non-breeding season in the marine environment. They are one of the least studied groups of ducks due to the inaccessibility of their predominantly Arctic breeding areas and marine wintering areas, where the cost of undertaking surveys, which usually involve boat and/or aerial surveys, is often prohibitive. However, there has been a vast improvement in both survey techniques and coverage in recent years, enabling some trend information to be gathered. Unfortunately, this has revealed that a number of seaduck populations are decreasing, some steeply, and three are now classified as globally threatened: Velvet Scoter, Long-tailed Duck and Steller’s Eider all qualify as Vulnerable (IUCN Red List of Threatened Species). Furthermore, at a European level Common Eider is classified as Vulnerable and Red-breasted Merganser is classified as Near Threatened (see European Red List of Birds 2015).

In most cases, reasons for the declines are unclear, however, a number of pressures have been identified as possible contributors, including oil pollution, aggregate extraction, ship traffic and other causes of displacement, ecological changes in prey-predator relationships in Arctic breeding areas and on the wintering grounds, and changes in food availability due to over-harvesting or changes in nutrient levels in the marine environment.

The species and populations of focus for the ESWG are listed below. For information on the boundaries of these populations see the Critical Sites Network Tool, and for information on current population size and trend visit Waterbird Population Estimates online.

	Greater Scaup    Aythya marila W Europe Black Sea / Caspian Sea
	Common Eider    Somateria mollissima S. m. mollissima (Britain/Ireland) S. m. mollissima (Baltic/Wadden Sea) S. m. mollissima (Norway/NW Russia) S. m. mollissima (White Sea) S. m. mollissima (Black Sea) S. m. faeroeensis (Faeroe Islands) S. m. faeroeensis (Shetland Islands) S. m. borealis (Svalbard/Franz Joseph Land) S. m. borealis (Iceland) S. m. borealis (NE Greenland)
	King Eider    Somateria spectabilis N Europe / W Siberia
	Steller’s Eider    Polysticta stelleri NW Europe
	Harlequin Duck    Histrionicus histrionicus Iceland
	Long-tailed Duck    Clangula hyemalis Iceland/Greenland W Siberia / N Europe
	Common Scoter   Melanitta nigra European
	Velvet Scoter    Melanitta fusca W European Black Sea
	Red-breasted Merganser   Mergus serrator NW & C Europe Mediterranean / Black Sea Greenland