Yellowstone’s first golden eagle marked with a transmitter
YELLOWSTONE NATIONAL PARK
A golden eagle was found dead on Dec. 6, 2018, near Phantom Lake in the northern section of Yellowstone National Park. A recent lab necropsy indicated the cause of death was lead poisoning. Levels found in the golden eagle were extremely high and well over lethal toxicity.
The adult female was the first golden eagle in Yellowstone’s history to be marked with a radio transmitter. The marked raptor was part of a study to understand productivity, movements, survival and cause of death in Yellowstone. The study is being conducted and funded by Yellowstone National Park, University of Montana, Yellowstone Forever and the U.S. Geological Survey.
Transmitter data revealed that the eagle ranged extensively during the 2018 autumn hunting season north of the park before it died. Hunter-provided carrion, especially gut piles, is an important food resource for golden eagles and other avian scavengers. The lead levels in the marked eagle indicated it likely ate carrion that contained lead fragments.
If carrion contain lead fragments, they can be deadly to scavengers. Lead is an environmental toxin well known for its capability to directly impact wildlife. Studies by Craighead Beringia South, a nonprofit research institute based in Kelly, Wyoming, have shown that fragmented bullets often stay in the discarded remains of wild game and subsequently enter the food chain as they are consumed by other animals. Lead poisoning can result when wildlife species ingest the toxic materials.
In November of 2011 and March 2015, Craighead Beringia South researchers from Livingston, Montana, also documented mortalities from elevated lead levels in two golden eagles that ranged north of the park.
Non-lead ammunition is safer for birds.
Golden eagles are large, long-lived raptors that feed on many medium-sized mammals, birds and carrion. Yellowstone considers golden eagles a species of concern.
Research biologist Ross Crandall of Craighead Beringia South says non-lead ammunition like copper or gilding metal is a great alternative for sportsmen. A hunter himself, he says he made the switch in 2005 not only for the benefits for wildlife, but also because of improved performance.
“A lot of hunters have switched because of performance. [Non-lead] has great ballistics and accuracy,” he said, adding that while premium lead ammunition is likely to be less expensive than premium non-lead, “In the grand scheme of things, a $45 box of ammo, I’d say, is really not worth that much especially when you might be saving the life of a golden eagle.”
Visit fws.gov/refuge/national_elk_refuge to read more about non-lead ammunition programs.
Visit nps.gov/yell/learn/resources-and-issues.htm to review Yellowstone’s Resources and Issues Handbook for more information about golden eagles.