Migration Trends for King and Common Eiders and Yellow-billed Loons past Point Barrow in a Rapidly Changing Environment

Many king (Somateria spectabilis), common eiders (S. mollissima v-nigra) and yellow-billed loons (Gavia adamsii) pass Point Barrow, Alaska, during spring and fall migrations. Spring migration counts of eiders at Point Barrow conducted since 1976 indicate that these species experienced population declines of approximately 50% between 1976 and 1996, and that the declines had stabilized by 2004. Similar estimates have not previously been performed for yellow-billed loons. We conducted spring counts of eiders and loons in 2015 and 2016 to compare with eider counts from 1994, 1995, 2003, and 2004, and loon counts from 2003 and 2004. We evaluated current and long-term trends in kind and common eider population indices, which appear to increase from 1994 through 2016. King eider indices were very different between 2015 and 2016, possibly due to a very short and intense peak migration in 2016 that was difficult to capture in population indices. The numbers of common eiders were similar between the two years, and within range of counts conducted in 2003–2004. Indices of yellow-billed loon populations suffered from other challenges, including high variability and migration through Pt. Barrow after when our counts ended in late May. These indices are important for conservation and subsistence management, but the techniques employed during this study need to be further refined to address the methodological challenges that we encountered, and further efforts should also anticipate the increasing difficulty of conducting these bird counts from the shorefast ice in spring.

USD: $62,977

2016-04-04 → 2018-04-19