Population Declines of King and Common Eiders of the Beaufort Sea

King (Somateria spectabilis) and Common Eiders (S. mollissima v-nigra) wintering off western North America migrate past Point Barrow, Alaska and across the Beaufort Sea to nest in northern Alaska and northwestern Canada. Migration counts were conducted by various researchers at Point Barrow during 1953, 1970, 1976, 1987, 1994, and 1996. We examined population trends by standardizing the analysis of the migration counts in all years. Based on this standardized procedure, the King Eider population appeared to remain stable between 1953 and 1976 but declined by 56% (or 3.9% year−1) from approximately 802,556 birds in 1976 to about 350,835 in 1996. The Common Eider population declined by 53% (or 3.6% year−1) from approximately 156,081 birds in 1976 to about 72,606 in 1996. Reasons for the declines are unknown.