ALBANY, N.Y (NEWS10) – Bald Eagles are suffering due to spent lead ammunition infecting their food sources. As numbers of spent lead ammunition climb, the eagle population faces potential population set back.
When a lead bullet makes contact with an animal, it breaks into many pieces, making it easily ingestible by eagles as it gets mixed in with their food sources. According to a study conducted by the Journal of Wildlife Management, the ingestion of used lead (Pb) ammunition is known to kill individual eagles.
The Journal of Wildlife Management hypothesized that mortalities from the ingestion of Pb reduced the long-term growth rate and resiliency of bald eagles in the northeast United States over the last 3 decades. They used Holling’s definition of resilience (the ability of a system to absorb changes of state variables, driving variables, and parameters and still persist) to quantify how a reduction in survival from Pb-associated mortalities reduced the likelihood of population persistence.
In a study conducted by the journal Science, researchers studied lead levels in over 1,000 eagles across 38 states. They found that more than half of the adult birds had bone lead concentrations above 10 parts per million, which pathologists define as chronic lead poisoning. The source of Pb that is most available to eagles and other scavenger birds, such as vultures, crows, and ravens.
Todd Katzner, a Supervisory Research Wildlife Biologist for the Forest and Rangeland Ecosystem Science Center, focuses on wildlife conservation ecology and the interaction between wildlife and the role of wildlife in natural systems. Katzner showed how vet records from autopsies on bald eagles, collected in the wild by state wildlife agency biologists, show that the ingestion of discarded ammunition containing used Pb ammunition fragments is a widespread cause of morbidity and mortality to eagles.
Assembly Bill A5728 prohibits the use of lead ammunition in the taking of wildlife on state-owned land and on land contributing surface water to the New York city water supply. While the Bald Eagle’s comeback has been a growing success since the band of the pesticide DDT in 1972, but lead bullets pose a new risk as mortality rates climb due to ingestion of spent lead ammunition.