A shot echoes through the woods: a deer falls, a knife is unsheathed, and a short time later all that is left behind is footprints and a small pile of internal organs. Soon, even that disappears. What happens to it?
Dr. Ellen Candler, a hunter herself, often found herself asking that question after field-dressing a deer.
“Everyone knows that something comes in, because then, you know, when you go back a week later to your spot it’s gone,” she said.
She had already been using remote trail cameras in her other research, so she set find the answers.
Candler, a postdoctoral researcher at the University of Minnesota, joined the KAXE Morning Show to discuss the Offal Wildlife Watching Project.
The project aims to discover what kinds of wildlife eat the gut piles (or offal) left behind by deer hunters, using trail cameras mounted near the offal sites. The project is currently recruiting bow hunters to participate.
With the help of Minnesota master naturalists and the Environment and Natural Resources Trust Fund, she recruited deer hunters to leave trail cameras behind. These cameras have captured over 230,000 images since the project’s beginning in 2018, with over 170 different sites monitored and over 47 species identified at the gut piles.
You’ve got to have guts to study offal
To the surprise of the research team, these photos have shown that other deer will occasionally feed on the gut piles. While this isn’t common — deer will more regularly investigate the remains but not cannibalize them — it was certainly an unexpected and somewhat macabre finding for Candler and her team.
These offal sites don’t just provide food for scavengers: they also are fruitful hunting grounds for predators such as owls. Small rodents will feed at the piles, and bobcats and owls have been photographed hunting these mice and voles, as well as feeding on the deer remains. (The bobcats were even photographed playing with the rodents!)
Candler’s team is now investigating whether owls find the gut piles independently and wait for prey to arrive, or if they follow the sound of prey to these sites (and enjoy a snack of deer guts afterward). Owls typically hunt by sight and sound, so presumably it would be difficult for them to find the stationary and silent gut piles independently.
Do owls hunt the mice, only to find them already sitting on a premade meal? It’d be like going to pick a strawberry and finding it already sitting on top of a milkshake!
Candler also seeks to learn how habitat types, nearby human populations, and how human-use patterns affect which wildlife species visit these sites.
“If we look at the number of individuals that come in — even if we just look at the crows and ravens combined — how many come to a gut pile in, you know, the conifer region versus the prairie region? How big are those groups?” Candler asked. “And then we can start to ask more questions about disease, potential transmission, or maybe survival. How do (human) hunters potentially help other scavenger species in (what is) kind of a lean time of year for a lot of animals?”
Do you have the stomach for it?
Currently, Candler and her team are recruiting hunters to participate in the project. With recent funding from the Environment and Natural Resources Trust Fund, the team now has trail cameras available to lend to participants. (Hunters can learn more about volunteering here.)
During the broadcast, KAXE Morning Show hosts Heidi Holtan and John Latimer received a text from Eric Newman attesting that Candler is a good keeper of deer stand locations.
“She asked for a location pin. I was hesitant, but after a few days, I shared mine. Just saying, I put a lot of trust in her!” Newman wrote.
Once placed, the cameras remain in place for about a month. Offal sites in the open are discovered by scavengers quite quickly and can be cleaned out in the matter of a week or two. Sites in deep forests may be unnoticed for longer, although crows, ravens and eagles often know to investigate when they hear a gunshot. (With 150,000-200,000 deer harvested every year, it’s not surprising that they’ve learned to associate the sound of a shot with the potential for food.)
Volunteers, whether they hunt or not, are also instrumental in categorizing and classifying the flood of photos that are produced each year. Using the citizen science website Zooniverse, volunteers examine images and determine what kind of animal, if any, is present at the site. So far, over 6,000 volunteers have participated in the classification efforts, identifying 47 species. (Learn more about this process here.)
