EXPOSURE OF SPECTACLED EIDERS AND OTHER DIVING DUCKS TO LEAD IN WESTERN ALASKA

Lead poisoning, resulting from ingestion of spent shot, has been ident ified as a cause of mortality in Spectacled Elders (Somateria fischeri ) on the Yukon-Kuskokwim Delta, Alaska. We examined lead-exposure rate s of adult and juvenile Spectacled Elders and other diving ducks, usin g atomic absorption spectrophotometry of blood samples. Additionally, we X-rayed birds in the field to identify ingested shot. We detected s hot in the gizzards of 11.6% of Spectacled Elders X-rayed. During the period from arrival through incubation, 13.0% of adult females and 6.6 % of adult males had elevated blood lead levels when captured. During the brood-rearing period, 35.8% of adult females and 12.2% of duckling s were exposed to lead when captured. There was an increase in the pro bability of exposure of adult females with date sampled. We predict th at 50% of the successfully breeding hens were likely exposed to lead, and 25-37% of the Spectacled Elder breeding population was exposed to lead. The long-term effects of sublethal doses on Spectacled Elders ar e unknown; however, exposure of nesting females and young birds to lea d may result in reduced over-winter survival and (or) reduced fecundit y.