After the government banned DDT in 1972, bald eagle populations slowly recovered from near devastation, but another ongoing problem weakened the repulsion-lead poisoning with ammunition.
New research published in Wildlife Management JournalFound that despite the increasing number of bald eagles, poisoning by eating dead carcasses and lead-contaminated areas reduced the population growth in the northeast by 4% to 6% each year. Did.
Due to the presence of copper-based ammunition, this result may help educate and inform hunters on ammunition selection policies. However, recently, the supply of all ammunition has been low.
Kristen Schuler, an assistant professor at Cornell University’s School of Public Ecosystem Health and lead author of the study, said, “I hope this report adds information that makes hunters as conservationists think about ammunition choices. I have. “
Declining growth rates can remove the cushion that protects the population from unforeseen events.
“The population seems to have recovered, but some turmoil could occur and the eagle could decline again,” Schuler said.
Habitat loss, climate change, West Nile virus, and other infectious diseases all affect the resilience of white-headed eagles and are threats that can lead to population declines, Schuler said.
The number of bald eagles in the 48 mainland U.S. states quadrupled between 2009 and 2021 to more than 316,000, but the 2021 U.S. Fish and Wildlife Service reports the current impact of lead on eagles. The findings show potential negative results for other species.
When bullets are fragmented and consumed within the game species, they can affect human health.
Many hunters “dressed” deer shot with lead bullets, leaving contaminated organs where the animals fell. Bald eagles are known to clean such carcasses, but they are not the only ones to do so. Trail cameras show that mammalian species such as owls, crows, coyotes, foxes, fishers, and bears are also cleaning what the hunters have left behind.
“We don’t collect data on these other species in the same way we pay attention to eagles,” Schuler said. “I’m using the eagle as a poster for this issue, but I’m not the only one affected.”
Despite an increase in the total number of eagles across the northeast between 1990 and 2018, researchers modeled a 4.2% (female) increase in bald eagle population due to death from lead intake. It was estimated to have decreased by 6.3% (male).
The study was funded by the Morris Animal Foundation, the New York State Department of Environmental Conservation, and federal aid to the Wildlife Restoration Act managed by the United States Fish and Wildlife Service.