Common eider (Somateria mollissima)

Eider (Somateria mollissima) (fig. 1) are a large and stocky seaduck with a distinctive wedge shaped bill. Adult male breeding plumage consists  of a mostly white body, black belly and pink blush on the chest. Crown is black and nape is a pale green. Adult female plumage is brown with dark barring all over. Eider will nest close to water along the coast. Their diet is largely crustaceans and molluscs such as sea mussels. Eider typically live to 14 years old, breeding at 3 years (Svensson et al, 2020; BTO, 2023).

Population & Distribution:
There are around 37,000 pairs of eider which breed in the UK each year (BTO, 2023). Eider are a common resident species and passage migrant to the East Grampian Coast. Forvie National Nature Reserve is home to Britain's largest breeding concentration of eider, although eider numbers and the breeding population have been steadily declining (fig. 2 & 3).

Alongside Forvie NNR, breeding has been recorded at a number of sites over the years along the East Grampian Coast including  Cairnblug, Loch of Strathbeg, Buchanhaven, Peterhead,and the Ugie Estuary. Throughout the year eider are recorded at sites including Girdle Ness, Peterhead, Ythan Estuary, and Blackdog/Murcar. Blackdog/ Murcar holds one of Britain’s largest single moulting flocks of eider (SOC North East Scotland Branch, n.d.).

Conservation Status:
Eider are an Amber listed species (Stanbury et al, 2021).

Factors Impacting Eider:
Along the East Grampian Coast, one of the largest factors determining breeding success for eider appears to be the weather, with warm dry summers showing good fledging success. Eider will hatch a high number of chicks but then high mortality rates before fledging occur due to cold and wet weather (e.g. heavy rain). Predation of chicks, probably by foxes (Vulpes vulpes), appears to have been a problem for eider breeding success. They are also vulnerable to human disturbance, both at their nesting sites and also on the estuary where human activity on the water can break up creches of chicks and leave them vulnerable to predation from gulls (SOC North East Scotland, n.d.). 

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