Local movements, home ranges and body condition of Common Eiders Somateria mollissima wintering in Southwest Greenland

• Main Authors: Merkel, Flemming R., Mosbech, Anders, Sonne, Christian, Flagstad, Annette, Falk, Knud, Jamieson, Sarah E.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2006
• Subjects: Body condition; Home range; Movements; Northern Common Eider; Satellite telemetry; Site fidelity; Southwest Greenland; Winter; Greenland; Nuuk; Common Eider; Somateria mollissima
• Online Access: https://pure.au.dk/portal/da/publications/local-movements-home-ranges-and-body-condition-of-common-eiders-somateria-mollissima-wintering-in-southwest-greenland(04f29005-a1f7-4f62-a8e2-86457e245f1f).html; http://www.scopus.com/inward/record.url?scp=34248230759&partnerID=8YFLogxK

We examined local movements, home ranges and body condition of wintering Northern Common Eiders Somateria mollissima borealis in Southwest Greenland from late winter until spring migration in 2000 and 2001. At key marine habitats at coastal areas and in the inner fjord system of Nuuk, we implanted 33 Eiders with satellite transmitters and collected Eider carcasses for body condition analyses. Most Eiders exhibited strong site fidelity during the study period with a mean 95% home range size of 67.8 km 2 and a mean core area (50%) of 8.1 km2. Diurnal movements peaked at dawn and dusk when birds presumably moved between feeding areas and roosting sites. Roosting occurred near daytime activity centres, on average 1.7 km apart. Among birds marked at coastal habitats only between 8% and 29% also used the inner fjord habitats, despite high levels of hunting at the coastal area. Birds that did move to the inner fjord system did not rerum to the coastal area. These findings accentuate the need for managing wintering Common Eiders in Southwest Greenland also at a local scale, taking site fidelity into account. The body condition of adult fjord birds was either equal or superior to that of coastal birds. However, within-years and between-years-variation in body condition were larger for fjord birds, suggesting that they were challenged by a higher unpredictability at the local scale. Observations indicate that differences in habitat characteristics and the behaviour of avian predators may limit the exchange of Eiders between the coastal area and the inner fjord system. Our study suggests that often Eiders build up body reserves for the breeding season elsewhere; in three of four cases adult body condition declined from late winter to early spring.