RESUMO
The king eider (Somateria spectabilis) is a migratory species of sea duck whose North American population is thought to be declining. We determined levels of cadmium, lead, selenium, and mercury in blood from female king eiders nesting in the central Canadian Arctic from 2001 to 2003. Year-to-year repeatability estimates were calculated from birds sampled in 2 or 3 years. Repeatability coefficients were 0.45, 0.35, 0.58, and 0.25 for cadmium, lead, selenium, and mercury, respectively. The first three were significantly different from zero (p < 0.05), whereas the last approached significance (0.05 < p < 0.1). In 2001 and 2002, we also identified probable wintering locations of a subset of the birds. In both years, cadmium levels were higher and selenium levels were lower in birds inferred to have wintered in the eastern part of their range compared to those that had wintered in the west. There was little evidence that timing of breeding, timing of sampling, or body condition were related to levels of these trace elements, although in 1 of 2 years, lead levels were influenced by body condition and nest initiation date (R(2) = 0.24) and cadmium levels were related to incubation day (partial R(2) = 0.04). Year-to-year repeatability of cadmium and selenium levels among individuals in this population of king eiders was likely influenced by where they wintered.
