Shooting prairie dogs creates an ecological double-edged sword. As an upside, dead prairie dogs offer scavengers a buffet of carcasses. But as a downside, that meal may be contaminated with fragments of lead bullets. Considering that millions of prairie dogs and other varmints are shot each year for damage control and recreation, scavengers have a good chance of filling their stomachs with some of that lead. A simple switch to nonlead ammunition eliminates that risk.
I’m a researcher for MPG Ranch in Montana’s Bitterroot Valley where lead poisoning in wildlife is a glaring issue. Between 2011 and 2018, our collaborators at Raptor View Research Institute found that nearly 95% of the golden eagles they caught in the winter had elevated levels of lead in their blood. Severe lead exposure can result in death, but more often, the eagles experience sublethal symptoms, like lack of coordination and weakness. These impairments spell bad news for birds that fend off coyotes from gut piles and sometimes migrate between Alaska and the lower 48.
The lead that eagles ingest can come from bullet fragments that end up in gut piles from hunting and the shooting of varmints, like prairie dogs and ground squirrels. A few years ago, my research team collected shot ground squirrels from agricultural fields, and a veterinarian X-rayed each one. Bullet fragments often peppered the carcasses, even if the bullet had exited. But we wondered: which scavengers eat these carcasses?
We set up game cameras across Montana to record which species scavenged shot ground squirrels and prairie dogs. Our study sites ranged from cattle pastures in White Sulphur Springs to sprawling prairie dog towns under the timbered hills of Ekalaka.
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The game cameras recorded 13 species of scavengers. We saw a burrowing owl perched atop a prairie dog near Terry, a badger devouring a late-night snack near Twin Bridges, and a red-tailed hawk south of Missoula, flying through the camera frame while piercing its talons through a ground squirrel’s ribcage. The variety of scavengers we observed made it clear that lead exposure was not limited to eagles.
The solution to this type of lead poisoning in wildlife is simple — shoot nonlead ammunition. In one of our previous studies, we found that nonlead bullets performed just as well on small game as their lead counterparts. Sporting goods stores are increasingly carrying nonlead options, particularly for popular rounds, like the .17 HMR, which costs the same as its lead equivalent. Online stores fill the gaps.
If you start chambering nonlead rounds, I’ll bet you won’t notice a difference in performance, but the scavengers might notice a difference in how they feel.