Minnesota deer hunters assist researchers in studying scavenger species

Once a deer hunter has successfully harvested and field-dressed a deer, a fascinating question arises: Which creatures emerge to scavenge the remaining internal organs?

This very question has been the area of focus for Offal Wildlife Watching researchers at the University of Minnesota Extension for the past five years. 

The Offal Wildlife Watching project is a research and citizen science project that aims to better understand scavenger interactions with hunter-derived food sources, such as gut piles, generally referred to as offal. The overall objective of the research is to study the variety of scavenger species across the different biomes in Minnesota. 

Since its inception in 2018, the research project has relied on deer hunters to place a trail camera near the offal for one month to document various scavenger species. After the month, the deer hunters submit the trail camera photos to the University of Minnesota Extension. 

“That’s some of the most fun to get these cameras back,” Ellen Candler, a Postdoctoral Associate at the University of Minnesota, said. “It’s just so exciting to see all the scavengers that come in.”

The Offal Wildlife Watching project has received over 230,000 trail camera images since 2018 and documented over 50 scavenger species. Candler said the variety of species includes flying squirrels, woodpeckers, eagles, crows, magpies, fishers, martens, and even other deer. 

However, one of the biggest surprises researchers have witnessed from the trail camera images is the behavior of barn owls using the offal as a prime location to hunt mice or voles. “So instead of a barn owl, just coming in to eat the guts, which we see them do. We’ve seen them eat mice or voles at the gut piles,” Candler said. Bobcats have also been recorded adopting this hunting strategy as well.

In the Northeast region of Minnesota, Candler said the images show that birds are generally the first scavengers to find the offal. “I think in the Arrowhead region, specifically, and then the coniferous zone, we noticed that birds are coming in right away. Like day one.” The results are interesting, Candler said, as in the southern prairie regions of the state, birds are not the first to arrive at the gut pile. 

Candler said approximately 170 deer hunters across Minnesota currently participate in the program, which provides a comprehensive snapshot of the diverse scavenger species. However, the Offal Wildlife Watching project invites more deer hunters to join the citizen science project. If a deer hunter wants to participate in the project but needs a trail camera, the project has trail cameras available to lend. 

“There’s also an opportunity to help us identify the images,” Candler said. While the Offal Wildlife Watching project is aimed at deer hunter participation, there are opportunities for naturalists or non-hunters to take part in the project. Interested individuals can view and classify trail camera images on Zooniverse. 

WTIP’s Kalli Hawkins spoke with Ellen Candler, a postdoctoral associate at the University of Minnesota, about the research and results of the ongoing Offal Wildlife Watching project. Audio from the interview is below. 

Kalli Hawkins October 31, 2023