Michele Mendi

A boreal and arctic sea duck with a circumpolar breeding distribution, though absent from Central N Siberia. Three subspecies are present in Europe, ssp. faeroensis breeds on Faeroe and islands off NW Scotland; ssp. borealis breeds in Iceland; ssp. mollissima is the commonest, breeding from W Siberia to the Atlantic coast of W Europe, wintering down Atlantic coasts to the N Mediterranean and rarely inland.

Season of assessment

B

Population trendDecreasing
Population size
(min-max, best estimate)		1220000-1630000,1410000
Red List categoryEN
Franks, S., Fiedler, W., Arizaga, J., Jiguet, F., Nikolov, B., van der Jeugd, Ambrosini, R, Aizpurua, O., Bairlein, F., Clark, J., Fattorini, N, Hammond, M., Higgins, D, Levering, H., Skellorn, W., Spina, F, Thorup, K. Walker, J., Woodward, I. and Baillie, S.R. (1) (2022) Online Atlas of the movements of European bird populations. https://migrationatlas.org EURING/CMS (1) Principal investigator
Map

Overall Connectivity for Common Eider

Birds breeding in Icelandi and the British Islesare mostly sedentary in winter. Baltic-breeding birds move  NE-SW, to join local breeders as far W as the Wadden Sea. A very few encounters link the Baltic to Scotland. There are recoveries connecting Spitzbergen birds with Iceland and N Norway. Birds tagged in winter in the Fehmarn Belt, off Denmark, moved along the Swedish coast to reach the Gulf of Bothnia and S Finnish coasts, confirming the pattern seen from recoveries.

Recoveries by Condition for Common Eider

As for many game ducks, most of the recoveries before 1961 are of dead birds (~88%), but this switched to most recoveries being of live birds in the most recent period (~75%). Most recoveries of dead birds are result of the large numbers hunted in Denmark (with smaller numbers shot in Sweden and parts of Finland, where they are also legal quarry), so the patterns described above should be considered in light of this bias.

Annual Movements for Common Eider

Given the small number of records of movements from the Gulf of Bothnia/Baltic to the Wadden Sea, annual movements are better understood from tracking data. Birds wintering in the Fehmarn Belt have already moved to the coasts of S Sweden by mid-Mar, to arrive on the breeding grounds by the end of Mar or early April. They move S during the last dekad of Jun, and return to the wintering grounds in early Jul. For tracked birds from Svalbard, autumn migration was late Aug-late Dec, and spring migration late Mar-late May (Hanssen et al. 2016). Birds breeding in Scotland have been recovered around the coasts of Denmark in the winter, while a few birds wintering in Scotland have been observed to move to the southern Gulf of Bothnia in May.

Connectivity by Month by Region for Common Eider

Birds wintering in the Wadden Sea are recovered in the Gulf of Bothnia May-Jul, most moving S to S Sweden and the Wadden Sea by Aug. Tracking data indicate returns to the Gulf of Bothnia in Apr, where they remain for the summer, with most females moving slightly S after the breeding attempt to moult in the N Baltic Sea. Males (and some failed/non-breeding females) undergo a moult migration away from the nesting areas often towards the winter quarters and so males and most females are in very different places at the same time of year.

Frédéric Jiguet

References

Statistics Map
N records N individuals N recoveries
Mapped data*
Total available data
*Mapped data include only distant (>= 50 km) recoveries
References Map
Hanssen, S.A., Gabrielsen, G.W., Bustnes, J.O. et al. 2016 . Migration strategies of common eiders from Svalbard: implications for bilateral conservation management. Polar Biology 39 Link to Article (DOI: https://doi.org/10.1007/s00300-016-1908-z) : 2179–2188

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