BLOOD LEAD CONCENTRATIONS OF SPECTACLED EIDERS NEAR THE KASHUNUK RIVER, YUKON DELTA NATIONAL WILDLIFE REFUGE, ALASKA

We collected 342 blood samples from spectacled eiders (Somateria fisch eri) on their breeding grounds in western Alaska from late May through to early August 1993-1995. Lead concentrations of greater than or equ al to 0.50 p.p.m. wet weight were found in the blood of 20% of the adu lt female eiders, 2% of the adult males and 6% of the ducklings. Lead was detected (greater than or equal to 0.02 p.p.m.) more frequently in the blood of adult females than in adult males or ducklings and the m aximum concentrations were 14.37, 0.50 and 4.28 p.p.m. wet weight, res pectively. In adult females, there was a significant difference in the proportion of detectable blood lead concentrations between three coll ection times (arrival/nesting, hatch and brood rearing), with the high est proportion (92%) occurring at hatch. Nine hens with blood lead con centrations of greater than or equal to 0.50 p.p.m. were captured a se cond time several weeks to 1 year later. In the hens sampled twice at intervals of several weeks, the blood lead concentrations increased an d declined at mean daily rates of 1.10 and 0.94, respectively. The lea d concentrations in the blood of adults were not correlated with body weights. Radiographs were taken of 119 eiders and corresponding blood samples from 98 of these birds were analysed for lead. Ingested shot w as seen in X-rays of 12 adults and three ducklings and, of the 13 bloo d samples tested, all had detectable lead concentrations. Of the birds without radiographic evidence of ingested shot, 84% of the adult fema les, 19% of the adult males and 17% of the ducklings had detectable le ad concentrations in their blood. Breeding ground exposure of waterfow l to lead shot is unusual and is of particular concern in spectacled e iders because of their threatened status and declining numbers in west ern Alaska.