Abstracts

Presented by Ray T. Alisauskas - Email: ray.alisauskas@canada.ca

We report on our long-term (1995-2016) mark-recapture study of female King Eiders nesting at Karrak Lake, Nunavut, in Canadas central arctic. We drew inference from 687 nesting adults females captured 1786 times and individually marked over 21 breeding seasons. We used Pradels models for estimating annual survival, per-capita recruitment and rate of population change; we also used a canonical estimator of abundance, from knowledge of numbers captured and capture probability. Furthermore, we considered ecological covariates, including 3 sources of integrated climate data during winter and spring migration, and on the nesting area to partition annual variation in survival, and local conditions at Karrak Lake to understand drivers of local population change. The North Pacific Index during winter and spring migration as well as the North Atlantic Oscillation during winter, each accounted for 21%, 30%, and 20% respectively, of annual variation in survival. We inferred that these patterns held for North American King Eider females that shared winter areas in both the North Pacific and North Atlantic waters. Covariates for annual variation in recruitment rate at Karrak Lake included timing of ice break up (25% ), number of nests (1%), and the North Pacific Index during spring migration (4%). Process variance of rate of population growth at Karrak Lake was 0.022, that of recruitment was 0.021 and that of survival was 0.002, showing that the main driver of population change at Karrak Lake was recruitment (r-square = 0.77) rather than survival (r-squared = 0.10). We use the strong links of recruitment and especially survival to integrated climate data to reconstruct and infer historical trends in relative population size for King Eiders that breed in North Americas arctic.