Lead exposure and poisoning in bald eagles and golden eagles in the Canadian prairie provinces

The prevalence of high lead exposure and lead poisoning was examined in dea d bald eagles and golden eagles from the Canadian prairie provinces from 19 90-96. Of 127 eagles, 12% were lead-poisoned based on lead concentrations > 20 ppm dry weight in kidney or 30 ppm in liver. A further 5% exhibited elev ated lead concentrations based on kidney lead concentrations >8 ppm or live r lead concentrations > 6 ppm. The prevalence of elevated lead concentratio ns did not differ (p = 0.23) between the two species although statistical p ower was low (0.4). When both species were combined, a higher proportion of adult and subadult birds had elevated tissue lead concentrations than imma ture birds (p<0.05). Golden eagles that exhibited high lead exposure were f ound closer to the hunting season than those that exhibited low lead exposu re (p=0.07) Such was not the case in bald eagles (p=0.89). There was a grea ter prevalence of high lead exposure in bald eagles found in areas of high waterfowl hunting intensity than in their counterparts found in areas of lo w waterfowl hunting intensity (p=0.07). In contrast, golden eagles with hig h lead exposure were associated with areas of lower waterfowl hunting activ ity than those with low lead exposure (p=0.04). In our study area, prevalen ces of lead poisoning in bald eagles and golden eagles were approximately e qual. For bald eagles, lead shot associated with waterfowl hunting was prob ably the main source of lead. Other sources of lead, including lead ammunit ion in upland game birds and mammals were more likely sources for golden ea gles. (C) 1999 Elsevier Science Ltd. All rights reserved.