Avian Scavengers And Lead Rifle Ammunition: Where We’re At, Challenges, And Solutions

Scientific Disciplines
Biological Sciences - Terrestrial
Environmental Sciences & Engineering
rifle ammunition
lead levels
Volume 17, No. 1-4

Avian scavengers and lead rifle ammunition:  
Where we’re at, Challenges, and solutions
Bryan Bedrosian,* Craighead Beringia South, P.O. Box 147, 6955 E 3rd St., Kelly, Wyoming 
83011, bryan@beringiasouth.org 
Derek Craighead, Craighead Beringia South, P.O. Box 147, 6955 E 3rd St., Kelly, Wyoming 83011  
Ross Crandall, Craighead Beringia South, P.O. Box 147, 6955 E 3rd St., Kelly, Wyoming 83011
Birds have long been recognized at risk of lead poisoning from ammunition sources, 
but only in recent years has rifle ammunition been identified as a source of lead toxicity in 
raptors and other scavenging birds. Several studies have indicated increased lead exposure in 
eagles but the implications to population dynamics remain unclear. We have monitored blood 
lead levels of Common Ravens (Corvus corax), Bald Eagles (Haliaeetus luecocehpalus), 
and Golden Eagles (Aquila chrysaetos) in Jackson Hole, Wyoming, since 2004 to investigate 
effects of spent rifle ammunition on avian scavengers. Data from ravens and Bald Eagles 
indicated a strong relationship between big-game hunting seasons and elevated blood lead 
levels. In 2009, we initiated a voluntary non-lead ammunition program in collaboration with 
Grand Teton National Park and the National Elk Refuge.  Free, non-lead ammunition was 
distributed to hunters in the area. Hunter surveys indicated that 24 percent of successful 
hunters on the Park and Refuge used non-lead ammunition and we detected a 28-percent 
drop in the mean lead levels of ravens monitored from previous years after the harvest totals 
were controlled for. We continued the voluntary program in 2010 by selling reduced-priced 
non-lead ammunition, and there was greater participation in the voluntary non-lead program 
(33%). Further, we have outfitted 13 Bald Eagles with satellite transmitters to document the 
potential geographic impact our local hunting season has on the continental eagle population 
and found that 90 percent of eagles outfitted during the big-game hunting season breed/
summer in central Canada.