The first study of lead poisoning of wildlife at a nationwide scale
This multi-year study finds high levels of lead in bald and golden eagles in 38 states. From the study, researchers noted that adult bald eagles were more frequently poisoned than juveniles and higher lead levels were lower in the summer than the fall or winter.
This is why we encourage hunters and anglers to “get the lead out.”
Read the summary posted on the USGS website.
You can also read the abstract for the paper, Demographic implications of lead poisoning for eagles across North America.
The conclusions of this study sound like what wildlife rehabilitators found in bald eagles in Iowa (Lead Poisoning in Bald Eagles Admitted to Wildlife Rehabilitation Facilities in Iowa, 2004-2014 PDF). Adult bald eagles had higher lead concentrations than immature or juvenile bald eagles. Lead concentrations were highest across all age classes during October-January.
The bar chart below has all the bald eagle admits from 2015-2020 that show the percentage of bald eagles tested for lead that have an elevated lead level. We look at these numbers by month of the year – so all January admits are together, regardless of year.