There are a multitude of threats to bald and golden eagles on the landscape and recent management efforts are focused on reducing anthropogenic causes of death in these species (1,2,3). Lead poisoning is a leading cause of mortality in eagles and studies have shown that lead concentrations spike in the blood and tissue of eagles during and directly following hunting seasons (3,4). Furthermore, recent research shows that lead poisoning is stunting population growth rates of bald and golden eagles at a nationwide scale (3,5). For this research project, we will formally test the efficacy of hunters voluntarily using non-lead ammunition through a rebate program that ultimately aims to reduce eagle fatalities in New York (6,7).
We will gauge the success of our non-lead rebate program by estimating the reduction in bald and golden eagle deaths. Our survey questions will focus on each hunter’s use of non-lead ammunition, whether they were successful in harvesting a deer, and whether they would consider participating in a similar program in the future. After the end of the 2023 hunting season, we will estimate the number of deer harvested with non-lead that would have otherwise been harvested with lead. From there, we can estimate the reduction in the number of eagle deaths within our target area using an advanced modeling approach (7).
1: Russell, R. E., & Franson, J. C. (2014). Causes of mortality in eagles submitted to the National Wildlife Health Center 1975–2013. Wildlife Society Bulletin, 38(4), 697-704.
2: U.S. Fish and Wildlife Service. (2016). Bald and Golden Eagles: Population demographics and estimation of sustainable take in the United States, 2016 update. Division of Migratory Bird Management, Washington D.C., USA.
3: Slabe, V. A., et al. (2022). Demographic implications of lead poisoning for eagles across North America. Science, 375(6582), pp.779-782.
4: Kelly, T. R., & Johnson, C. K. (2011). Lead exposure in free-flying turkey vultures is associated with big game hunting in California. PLoS One, 6(4), e15350.
5: Hanley, B. J., Them, C. E., Hynes, K. P., Connelly, P. J., Bunting, E. M., Schuler, K. L. (2023). Population impact to bald eagles by ingested lead in New York State, 1990–2018. Wildlife Society Bulletin, e1444.
6: Kelly, T. R., Bloom, P. H., Torres, S. G., Hernandez, Y. Z., Poppenga, R. H., Boyce, W. M., & Johnson, C. K. (2011). Impact of the California lead ammunition ban on reducing lead exposure in golden eagles and turkey vultures. PLoS One, 6(4), e17656.
7: Cochrane, J. F., Lonsdorf, E., Allison, T. D., & Sanders-Reed, C. A. (2015). Modeling with uncertain science: estimating mitigation credits from abating lead poisoning in Golden Eagles. Ecological Applications, 25(6), 1518-1533.