Lead Exposure is Unrelated to Wind Turbine Mortality in Golden Eagles

Lead toxicosis is well established as an important contributor to mortalities in bald and golden eagles (Haliaeetus leucocephalus and Aquila chrysaetos, respectively), California condors (Gymnogyps californianus), and a variety of waterfowl. The effects of lead toxicosis may predispose birds to traumatic encounters, such as collision with power lines. Rotating wind turbine blades have caused the death of many bird species, including bald and golden eagles, when flight paths intersect wind farms. We conducted an analysis of the relationship between liver lead concentrations and mortality from collisions with wind-turbine blades (WT) in golden eagles submitted to the National Fish and Wildlife Forensic Laboratory (NFWFL) from 2011 to 2016 from across the United States. During that time, 116 golden eagles were determined to have died of wind turbine blade collision and 52 were tested for lead exposure. Liver lead concentrations in our sample were compared to those from 25 golden eagles that died of other causes including electrocution, gunshot, and other trauma. Eagles that died from wind turbine blade collision had lower (P < 0.01) lead concentrations (geometric mean 0.25 ppm wet weight [ww]; median 0 ppm ww) than those with other mortality factors (geometric mean 0.65 ppm ww; median 0.42 ppm ww). Across both control (non-WT mortality) and WT groups, liver lead concentrations did not differ significantly between males and females (P = 0.95), or between adults and sub-adults (P = 0.45). The ratios of life stages and sexes in the WT group were similar to that of the broader population of golden eagles submitted to NFWFL during the same time period. Published 2021. This article is a U.S. Government work and is in the public domain in the USA.

Automated summary

Lead toxicosis poses a threat to bald eagles, golden eagles, California condors, and various waterfowl, potentially leading to their deaths. A study revealed that golden eagles that died from wind turbine blade collision had lower liver lead concentrations compared to those that died from other causes.