Blood-Lead Levels of Wintering Golden and Bald Eagles of the Bitterroot Valley Montana (Poster)
AbstractLead has long been documented as a serious environmental hazard to eagles and other predatory, opportunistic and scavenging avian species. The use of lead shotgun pellets for waterfowl hunting on federal and state lands was banned in 1991 due to lead poisoning in Bald Eagles (Haliaeetus leucocephalus), Golden Eagles (Aquila chrysaetos) and numerous waterfowl species. At that time, this was thought to be the major source of the lead exposure. More recently, lead poisoning from ingested lead-bullet fragments and shotgun pellets has been identified as the leading cause of death in California Condors (Gymnogyps californianus), leading to a ban of lead ammunition within the “California Condor Recovery Zone.” Another on-going study on Common Ravens (Corvus corax) and Bald Eagles in Wyoming has shown a direct correlation between very high blood-lead levels and the on-set of rifle hunting season. Indeed, there is overwhelming evidence showing that lead toxicity is still prevalent in the environment and mounting data points to fragmented rifle bullets as the source. We sampled blood from 32 Golden Eagles and 11 Bald Eagles captured on wintering grounds in the Bitterroot Valley from 2011 - Present. Eighty-six percent of eagles tested showed blood-lead concentrations higher than natural background levels. These preliminary results suggest exposure to lead is prevalent among eagles from northern latitudes wintering in the Bitterroot Valley.
Montana Chapter of The Wildlife Society [Abstracts]