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.
Non-lead alternatives[
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.
