Block title

black-tailed prairie dog, Columbian Ground Squirrel, burrowing owl, Red Fox, Northern harrier, Common raven
Research Projects: 
Raptor Blood Lead Monitoring, Avian Ecology
Research Methods: 
Shooting prairie dogs and ground squirrels (i.e., gophers) is controversial. To some people, firing bullets at these burrowing mammals seems unethical. To others, it’s recreation, or damage control to protect crops and cattle forage. Either way, the carcasses provide a feast for scavengers. Yet, little is known about which scavengers do the feasting.

Along with our colleague, Dr. Brian Hiller at Bemidji State University, we set up game cameras near 89 carcasses at eight ranches and private properties across Montana. The Journal of Wildlife Management just published our work, but here’s a rundown of the main findings.

Scavengers fully consumed 66% of the carcasses and partially consumed 9% of them. We observed five species of mammals and nine species of birds, like northern harriers (pictured below). Birds ate 84% of the carcasses, and mammals ate the rest. Of the birds that scavenged, half were raptors and half were corvids. We were surprised to see burrowing owls scavenging. They often feed opportunistically, but to our knowledge they hadn’t been seen scavenging prairie dog carcasses.

Carcasses didn’t last long. On average, scavengers like the fox below fully consumed or carried away carcasses in 24.5 hours.

In White Sulphur Springs, MT, common ravens scavenged nearly every carcass even though hawks soared overhead. The presence of the first raven at a carcass may have lured in more ravens, potentially speeding up the rate of scavenging.

Unfortunately, there’s no “free lunch.” Our previous research in Wildlife Society Bulletin (summarized here), showed that even if lead bullets pass through a ground squirrel, tiny fragments of lead can be left behind (X-ray below). If a scavenger ingests those fragments it may be poisoned. Shooters can eliminate this risk and feed scavengers “clean” carcasses by using nonlead ammunition.

About the Author

Mike McTee

Mike McTee is a researcher at MPG Ranch and the author of Wilted Wings: A Hunter’s Fight for Eagles.

Mike shot his first weapon before he could recite the alphabet. Now, understanding weapons is part of his job. His career took this trajectory after Mike gained a B.S. in Environmental Chemistry. Curious about potential pollution at a historic shooting range at MPG Ranch, he earned an M.S. in Geosciences studying the site. Strangely, the sulfur inside the trap and skeet targets posed the main threat, not the lead in the shotgun pellets. Regardless, lead contamination soon grabbed Mike’s focus. Each winter at MPG Ranch, biologists caught eagles that had lead coursing through their veins. Lead can cripple eagles flightless and even kill them. Mike soon initiated studies on scavenger ecology and began investigating the wound ballistics of rifle bullets, the suspected source of lead.

Mike often connects with the public through his writings and speaking engagements, whether it be to a local group of hunters, or a gymnasium full of middle schoolers. He frequently writes about the outdoors, with work appearing in Sports Afield, The Drake, and Bugle. When he escapes the office, Mike explores wild landscapes with his family, always scanning the horizon for wildlife.

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