The Eider Pass at Point Barrow, Alaska

Thompson, Daniel; Person, Richard

Daily observations were made on king (Somateria spectabilis) and Pacific eiders (Somateria mollissima v. nigra) at the 'Duck Camp,' Point Barrow, Alaska, July 14-September 1, 1953. Mean flock size was 105 birds from a sample of 497 flocks. The flight was segregated as to sex and age. In the period August 8-17, the king eider sex ratio shifted from a preponderance of males to a preponderance of females. The mean weight of 41 adult king eider males (1,668 grams) differed from the mean weight of 140 adult females (1,567 grams) at a high level of significance. Limited observations on molt phenology indicated a relatively high degree of synchronization of molt pattern within each sex. Molt of body plumage had reached the caudal tract in king eider males by August 14; females were not so far advanced. Peak eider flights tended to occur with favorable winds; however, the birds were not sensitive to wind velocities below 9 miles per hour. An average of 987 eiders per hour was recorded in 46 days of observation in 1953. The average number of hunters per hour was 4.1. In their average performance, these 4.1 hunters fired 11.5 shots, killed 3.5 eiders, and failed to recover 1.5 cripples per hour. Total mortality to southbound adult eiders from Point Barrow hunters was estimated to be 0.5 percent in 1953.

The Eider Pass at Point Barrow, Alaska

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