EFFECT OF LEAD-POISONING ON SPECTACLED EIDER SURVIVAL RATES

Spectacled elder (Somateria fischeri) populations on the Yukon-Kuskokw im Delta (Y-K Delta), Alaska, declined rapidly through the 1980s, and low adult female survival was suggested as the likely cause of the dec line. We used mark-resighting techniques to study annual survival rate s of adult female spectacled elders at 2 sites on the Y-K Delta during 1993-96. Our data suggest survival rates may differ among sites. Howe ver, a model fit to a subset of data on females for which we knew lead levels in blood suggests lead exposure influences survival. Adult fem ales exposed to lead prior to hatching their eggs survived at a much l ower rate (0.44 +/- 0.10) each year than females not exposed to lead b efore hatch (0.78 +/- 0.05). We suggest most mortality from lead expos ure occurs over winter, and the related reduction in adult survival ma y be impeding recovery of local populations. We encourage managers to curtail input of lead shot into the environment.