Evidence of population decline in Common Eiders breeding in western Greenland

摘要

In the Arctic, there is great concern for several eider populations, including the northern common eider (Somateria mollissima borealis) breeding in Canada and Greenland. In 1998–2001, extensive ground surveys were conducted on 937 potential nesting islands in West Greenland, covering most of the districts of Ilulissat, Uummannaq, and Upernavik (69°15' N to 74°05' N). On 216 islands within 106 eider colonies, 4097 ± 468 active nests were identified. In 15 colonies where comparable and well-documented surveys were conducted approximately 40 years ago, the study shows a population decline of 81% (from 3361 to 624 nests). A rough comparison shows that of 51 eider colonies surveyed in 1920, 1960, or 1965, 71% either were gone or had declined in breeding numbers when resurveyed in 1998–2001. At the colony level, the 1998–2001 surveys revealed large year-to-year variations in nesting numbers. The reason for the overall decline is not clear. However, there is circumstantial evidence that harvest of common eiders in West Greenland is a key factor. The results urgently call for more cautious management of the northern common eider population.