About Somateria mollissima (Linnaeus, 1758)
The common eider, scientifically named Somateria mollissima (Linnaeus, 1758), is both the largest of the four eider species and the largest duck found in Europe. In North America, only scattered populations of the Muscovy duck exceed the common eider in size; Muscovy ducks only occur in a wild state in the southernmost part of Texas, with feral non-native populations also present in southern Florida that are sometimes considered to count towards this size comparison. This duck measures 50 to 71 cm (19+1⁄2 to 28 in) in overall length, weighs 0.81 to 3.04 kg (1 lb 12+1⁄2 oz to 6 lb 11 oz), and has a wingspan of 80–110 cm (31–43 in). The average weight of 22 adult males from the North Atlantic was 2.21 kg (4 lb 14 oz), while 32 adult females from this region had an average weight of 1.92 kg (4 lb 3+1⁄2 oz). The common eider has a characteristic bulky body shape and a large, wedge-shaped bill. Breeding males have distinctive plumage: they are patterned black and white, with a green nape. Females are solid brown birds, but can be readily distinguished from all duck species except other eiders by their large size and unique head shape. Displaying male common eiders produce a unusual, almost human-like call that sounds like "ah-ooo", while females make hoarse quacking sounds. Individuals of this species are often easily approached by people. Minor differences in plumage and bill color separate the common eider subspecies that occupy Europe, eastern North America, and Asia/western North America. Some taxonomic authorities recognize the subspecies v-nigra as a full separate species. Common eiders dive to forage for crustaceans and molluscs, and mussels are their preferred food. They swallow whole mussels, after which the mussel shells are crushed in the bird's gizzard and excreted. When feeding on crabs, common eiders first remove all the crab's claws and legs before eating the body whole in the same manner as they consume mussels. The common eider is an abundant species, with an estimated total population of 1.5 to 2 million birds across both North America and Europe, with large but uncounted populations present in eastern Siberia, as cited by HBW. A well-known colony of common eiders nests annually on the Farne Islands in Northumberland, England, with around 1,000 breeding pairs recorded there each year. Claims have circulated that this colony was protected by one of the earliest ever bird protection laws, and that the first wildlife preserve was created for these eiders by Saint Cuthbert in 676, but these claims are not supported by evidence. No mention of Saint Cuthbert having a connection to these birds appears in any historical documents until a story was published roughly 500 years after his death. The later stories that mention Cuthbert and eiders also do not discuss any modern conservation concerns such as habitat loss. Because Saint Cuthbert is the patron saint of Northumberland, the common eider was chosen as the county's official emblem bird. In the local area, common eiders are still often called St Cuthbert's ducks or Cuddy's ducks, where Cuddy is the common familiar shortened form of the name Cuthbert. In the 1990s, local populations observed major die-offs of common eiders in Canada's Hudson Bay, caused by rapidly changing ice flow patterns. The Canadian Wildlife Service conducted multiple years of research to collect updated population data, and preliminary results suggest the local population has recovered. The common eider is the central subject of the 2011 documentary People of a Feather, which examines the historical relationship between the Sanikiluaq community and these ducks, alongside multiple aspects of common eider ecology. This species is covered by the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA).
