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Common Eider Somateria mollissima

This species has been uplisted to Near Threatened. Within Europe it has experienced moderate declines and these have not been compensated for by increases elsewhere in the species's range. Declines are thought to be driven by a range of threats including overharvesting of aquatic resources, pollution, disturbance and hunting. Should the declines be found to be more severe, or new information reveal declines in the S. m. sedentaria and S. m. borealis populations then the species would warrant uplisting; it almost meets the requirements for listing as threatened under criterion A4abcde.

Taxonomic source(s)
AERC TAC. 2003. AERC TAC Checklist of bird taxa occurring in Western Palearctic region, 15th Draft. Available at: # _the_WP15.xls#.
Cramp, S.; Perrins, C. M. 1977-1994. Handbook of the birds of Europe, the Middle East and Africa. The birds of the western Palearctic. Oxford University Press, Oxford.
del Hoyo, J.; Collar, N. J.; Christie, D. A.; Elliott, A.; Fishpool, L. D. C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Barcelona, Spain and Cambridge UK: Lynx Edicions and BirdLife International.

50-71 cm. Breeding male very distinctive with black coronal region, divided by white streak over central crown to nape (Carboneras et al. 2014). Rest of head white with pale green patches on nape and rear-ear coverts. Upperparts white, breast rosy-pink, rump, tail and rest of underparts black. Bill olive-grey with pale yellow tip. Female warm brown with black bars. Juveniles resemble female. Voice Characteristic cooing call between autumn and spring, otherwise generally silent.

Distribution and population
The species is distributed over the northern coasts of Europe, North America, eastern Siberia and southern Greenland. It breeds in the Arctic and northern temperate regions, but its range expands during winter to as far south as New Jersey, southern Alaska (U.S.A.), the western Mediterranean and the southern tip of the Kamchatka Peninsula (Russia) (del Hoyo et al. 1992). There are four subspecies in North America: Pacific (S. mollissima v-nigra), American (S. m. dresseri), Hudson Bay (S. m. sedentaria), and Northern (S. m. borealis) (Bowman et al. 2015).

Population justification
The global population is estimated to number c. 3,300,000-4,000,000 individuals (Wetlands International 2012). The European population is estimated at 791,000-955,000 pairs, which equates to 1,580,000-1,910,000 mature individuals (BirdLife International 2015).

Trend justification
In Europe the population size is currently declining overall at a rate of >40% over three generations (27 years) (BirdLife International 2015). A decline has been evident since the late 1990s in the largest flyway population of S. m. mollissima in the Baltic and Wadden Seas, based both on breeding data (Ekroos et al. 2012) and on midwinter counts conducted as part of the International Waterbird Census (Nagy et al. 2014). Rapid declines have been reported for the islands of Gotland (from 7,140 nesting females in 2007 to 1,310 in 2015) and Öland in the Baltic Sea (K. Larsson in litt. 2015). Europe (including Greenland) holds >60% of the global population (Wetlands International 2012), so the declines in Europe are globally significant.

The remainder of the population occurs in North America where population trends are variable. The Pacific population, S. m. v-nigra, which represents c. 4% of the global population is thought to have declined in the northern parts of its range between the 1980s and early 2000s and in central Arctic Canada and north-west Alaska it has declined but appears to be increasing in the rest of Alaska (Bowman et al. 2015). The American population, S. m. dresseri, (c. 9% global population) shows variable trends with the northern population increasing and southern population decreasing. Trends are uncertain for the Hudson Bay, S. m. sedentaria, (c. 6% global population) and Northern, S. m. borealis, (c. 16% global population) populations. Given the strong declines in the European population and a lack of compensatory increases in the North American population the overall population trend is thought to be declining moderately rapidly.

The species breeds on offshore islands and islets (Kear 2005) along low-lying rocky coasts (del Hoyo et al. 1992), on coastal shores and spits, on islets in brackish and freshwater lagoons (Kear 2005), lakes and rivers (Johnsgard 1978) close to the sea (Kear 2005) or on tundra pools, rivers (del Hoyo et al. 1992) and lakes (Madge and Burn 1988) up to 5 or 6 km inland (Kear 2005). It shows a preference for boulder-strewn or grassy islands (Johnsgard 1978) with sheltered approaches that are safe from nest predators, although in the high Arctic where such shelter is unavailable more open sites must be used (in which case the species often nests in closely packed groups for protection) (Snow and Perrins 1998). The species typically moults on shallow marine or sheltered coastal waters (Kear 2005), and winters on shallow seashores, bays and estuaries (del Hoyo et al. 1992), especially where there are high abundances of benthic molluscs (Camphuysen et al. 2002, Ens 2006). It may also occur inland on freshwater lakes when on passage and during the winter (rarely) (Madge and Burn 1988). The nest is a slight hollow in the ground that is usually positioned in the shelter of rocks or vegetation but may also be in the open (del Hoyo et al. 1992). Its diet consists predominantly of benthic molluscs although crustaceans (del Hoyo et al. 1992) (e.g. amphipods and isopods (Johnsgard 1978)), echinoderms, other marine invertebrates and fish may also be taken (del Hoyo et al. 1992). During the breeding season incubating females frequently complement their diet with algae, berries and the seeds and leaves of surrounding tundra plants (del Hoyo et al. 1992). The majority of this species is migratory (Flint et al. 1984) (although it does not travel great distances) (Madge and Burn 1988, Snow and Perrins 1998), with some populations e.g. in Europe being largely sedentary (Scott and Rose 1996).

The species is vulnerable to chronic coastal oil pollution (Nikolaeva et al. 2006), especially oil spills (del Hoyo et al. 1992, Kear 2005, Nikolaeva et al. 2006), in areas where large moulting and wintering concentrations occur (del Hoyo et al. 1992). It also comes into conflict with the shellfish aquaculture industry which depletes the species's food resources (Kear 2005, Ens 2006, Nikolaeva et al. 2006,) and has previously lead to mass starvation events due to the over-fishing of benthic molluscs (e.g. in the Dutch Wadden Sea) (Camphuysen et al. 2002, Ens 2006). On the breeding grounds disturbance from the development of mineral resources along the coast (Nikolaeva et al. 2006) and from local shore-based activities (e.g. angling, dog-walking [Keller 1991] and other recreational activities such as boat tours [Burnham et al. 2012] as well as scientific research [Bolduc and Guillemette 2003]) increases the likelihood of predation on young (Keller 1991). Unregulated tourism and shipping also cause disturbance to the species on its wintering grounds (Nikolaeva et al. 2006)

The species commonly becomes entangled and drowned in monofilament nets (Kear 2005) (e.g. gillnets (Merkel 2004)), and it is hunted unsustainably (Nikolaeva et al. 2006) (e.g. in Denmark [Bregnballe et al. 2006] and Greenland [Merkel 2004]). Populations of this species in the high Arctic are subject to shooting, especially in spring, by indigenous peoples for food (Byers and Dickson 2001, Kear 2005). This subsistence hunting is likely to be sustainable at current levels (Byers and Dickson 2001). The species is also shot for sport in North America (this harvest may exceed sustainable levels in some areas [Kear 2005]). Increased levels of predation, including by White-tailed Eagle Haliaeetus albicilla may be responsible for recent increases in female mortality in some areas (Ekroos et al. 2012). Avian cholera represents a new threat, capable of wiping out colonies of this species (Descamps et al. 2012, Tjørnløv et al. 2013). The species may also be sensitive to the effects of climate change (Carboneras et al. 2012).

Conservation and Research Actions Underway
EU Birds Directive Annex II and III. CMS Appendix II. Changes to hunting regulations in Greenland in 2001 shortened the length of the hunting season which is thought to have led to a rapid increase in population size (Burnham et al. 2012). However the hunting regulations have recently changed and the effect on the population is not yet known. Restrictions were also introduced in Denmark in 2004/2005 and 2011/2012 with the aim of reducing the proportion of female birds killed and increasing the population growth rate (Christensen and Hounisen 2014).

Conservation and Research Actions Proposed
Sustainable levels of hunting should be established in those areas where the species is harvested and legislation established and enforced to ensure this. Conduct flyway-scale winter counts (Ekroos et al. 2012) and ensure monitoring is coordinated across the species's range (I. K. Petersen in litt. 2015). Key areas should be protected from all forms of disturbance as well as oil exploration, drilling and transportation. Levels of shellfish harvesting should be monitored to ensure sustainability and measures to minimise bycatch in fishing nets promoted amongst fisheries. International monitoring plans should be developed and a programme of research put in place, while taking precautions to minimise the impact of scientific work.

Related state of the world's birds case studies

BirdLife International. 2015. European Red List of Birds. Office for Official Publications of the European Communities, Luxembourg.

Bolduc, F.; Guillemette, M. 2003. Human disturbance and nesting success of Common Eiders: interaction between visitors and gulls. Biological Conservation 110: 77-83.

Bowman, T.D., Silverman, E.D., Gilliland, S.G. and Leirness, J.B. 2015. Status and trends of North American sea ducks: reinforcing the need for better monitoring. In: Savard, J.-P.L., Derksen, D.V., Esler, D. and Eadie, J.M. (eds), Ecology and conservation of North American sea ducks. Studies in Avian Biology (no. 46), pp. 1-28. CRC Press, Boca Raton, FL.

Brazil, M. 2009. Birds of East Asia: eastern China, Taiwan, Korea, Japan, eastern Russia. Christopher Helm, London.

Bregnballe, T., Noer, H., Christensen, T.K., Clausen, P., Asferg, T., Fox, A.D. and Delany, S. 2006. Sustainable hunting of migratory waterbirds: the Danish approach. In: G. Boere, C. Galbraith, and D. Stroud (eds), Waterbirds around the world, pp. 854-860. The Stationary Office, Edinburgh, UK.

Burnham, K.K., Johnson, J.A., Konkel, B. and Burnham, J.L. 2012. Nesting Common Eider (Somateria mollissima) Population Quintuples in Northwest Greenland. Arctic 65(4): 456-464.

Byers, T.; Dickson, D .L. 2001. Spring migration and subsistence hunting of king and common eiders at Holman, Northwest Territories, 1996-98. Arctic 54(2): 122-134.

Camphuysen, C. J.; Berrevoets, C. M.; Cremers, H. J. W. M.; Dekinga, A.; Dekker, R.; Ens, B. J.; van der Have, T. M.; Kats, R. K. H.; Kuiken, T.; Leopold, M. F.; van der Meer, J.; Piersma, T. 2002. Mass mortality of common eiders (Somateria mollissima) in the Dutch Wadden Sea, winter 1999/2000: starvation in a commercially exploited wetland of international importance. Biological Conservation 106: 303-317.

Carboneras, C., Christie, D.A. and Kirwan, G.M. 2014. Common Eider (Somateria mollissima). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. and de Juana, E. (eds), Handbook of the Birds of the World Alive, Lynx Edicions, Barcelona.

Christensen, T.K. and Hounisen, J.P. 2014. Managing hunted populations through sex-specific season lengths: a case of the Common Eider in the Baltic-Wadden Sea flyway population. European Journal of Wildlife Research 60(5): 717-726.

del Hoyo, J.; Elliot, A.; Sargatal, J. 1992. Handbook of the Birds of the World, vol. 1: Ostrich to Ducks. Lynx Edicions, Barcelona, Spain.

Delany, S.; Scott, D. 2006. Waterbird population estimates. Wetlands International, Wageningen, The Netherlands.

Descamps, S., Jenouvrier, S., Gilchrist, H.G. and Forbes, M.R. 2012. Avian cholera, a threat to the viability of an Arctic seabird colony? PLoS ONE 7(2): e29659.

Ekroos, J., Fox, A.D., Christensen, T.K., Petersen, I.K., Kilpi, M., Jónsson, J.E., Green, M., Laursen, K., Cervencl, A., de Boer, P., Nilsson, L., Meissner, W., Garthe, S. and Öst, M. 2012. Declines amongst breeding Eider Somateria mollissima numbers in the Baltic/Wadden Sea flyway. Ornis Fennica 89: 81-90.

Ens, B. J. 2006. The conflict between shellfisheries and migratory waterbirds in the Dutch Wadden Sea. In: Boere, G.; Galbraith, C., Stroud, D. (ed.), Waterbirds around the world, pp. 806-811. The Stationary Office, Edinburgh, UK.

Flint, V.E., Boehme, R.L., Kostin, Y.V. and Kuznetsov, A.A. 1984. A field guide to birds of the USSR. Princeton University Press, Princeton, New Jersey.

Heide-Jorgensen, M. P.; Laidre, K. 2004. Declining extent of open-water refugia for top predators in Baffin Bay and adjacent waters. Ambio 33: 487-494.

IUCN. 2015. The IUCN Red List of Threatened Species. Version 2015-4. Available at: (Accessed: 19 November 2015).

Johnsgard, P.A. 1978. Ducks, geese and swans of the World. University of Nebraska Press, Lincoln and London.

Kear, J. 2005. Ducks, geese and swans volume 2: species accounts (Cairina to Mergus). Oxford University Press, Oxford, U.K.

Keller, V. E. 1991. Effects of human disturbance on Eider ducklings Somateria mollissima in an estuarine habitat in Scotland. Biological Conservation 58: 213-228.

Lehikoinen, A.; Kilpi, M.; Öst, M. 2006. Winter climate affects subsequent breeding success of common eiders. Global Change Biology 12: 1355-1365.

Madge, S. and Burn, H. 1988. Wildfowl. Christopher Helm, London.

Merkel, F. R. 2004. Impact of hunting and gillnet fishery on wintering eiders in Nuuk, southwest Greenland. Waterbirds 27(4): 469-479.

Nagy, S., Flink, S. and Langendoen, T. 2014. Waterbird trends 1988-2012: Results of trend analyses of data from the International Waterbird Census in the African-Eurasian Flyway. Wetlands International, Ede.

Nikolaeva, N.G., Spiridonov, V.A. and Krasnov, Y.V. 2006. Existing and proposed marine protected areas and their relevance for seabird conservation: a case study in the Barents Sea region. In: G. Boere, C. Galbraith and D. Stroud (eds), Waterbirds around the world, pp. 743-749. The Stationary Office, Edinburgh, UK.

Scott, D. A.; Rose, P. M. 1996. Atlas of Anatidae populations in Africa and western Eurasia. Wetlands International, Wageningen, Netherlands.

Snow, D.W. and Perrins, C.M. 1998. The Birds of the Western Palearctic, Volume 1: Non-Passerines. Oxford University Press, Oxford.

Tjørnløv, R.S., Humaidan, J. and Frederiksen, M. 2013. Impacts of avian cholera on survival of Common Eiders Somateria mollissima in a Danish colony. Bird Study 60(3): 321-326.

Vahatalo, A. V.; Rainio, K.; Lehikoinen, A.; Lehikoinen, E. 2004. Spring arrival of birds depends on the North Atlantic Oscillation. Journal of Avian Biology 35: 210-216.

Wetlands International. 2012. Waterbird Population Estimates: 5th Edition.

Further web sources of information
Detailed regional assessment and species account from the European Red List of Birds (BirdLife International, 2015)

Detailed species account from Birds in Europe: population estimates, trends and conservation status (BirdLife International 2004)

Explore HBW Alive for further information on this species

Search for photos and videos, and hear sounds of this species from the Internet Bird Collection

Text account compilers
Ashpole, J, Burfield, I., Butchart, S., Calvert, R., Ekstrom, J., Ieronymidou, C., Malpas, L., Pople, R., Wheatley, H. & Wright, L

Drysdale, A., Gudmundsson, G., Larsson, K., Meltofte, H., Petersen, I., Pihl, S. & Waltho, C.

IUCN Red List evaluators
Symes, A.

Recommended citation
BirdLife International (2015) Species factsheet: Somateria mollissima. Downloaded from on 29/11/2015. Recommended citation for factsheets for more than one species: BirdLife International (2015) IUCN Red List for birds. Downloaded from on 29/11/2015.

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

To provide new information to update this factsheet or to correct any errors, please email BirdLife

To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.

Additional resources for this species

ARKive species - Common eider (Somateria mollissima) 0

Key facts
Current IUCN Red List category Near Threatened
Family Anatidae (Ducks, Geese, Swans)
Species name author (Linnaeus, 1758)
Population size mature individuals
Population trend Unknown
Distribution size (breeding/resident) 3,320,000 km2
Country endemic? No
Links to further information
- Additional Information on this species
- 2015 European Red List assessment