Michigan coyotes in most of the Lower Peninsula are the “top dogs” in the local food chain and can dine on a wide variety of small animals, including rabbits and rodents, along with berries and other plant foods, insects, human garbage and even outdoor pet food.

But in the Upper Peninsula, coyotes coexist with gray wolves and play a subordinate role in the food web. As a result, the diets of U.P. coyotes contain less meat than Lower Peninsula coyotes.

That’s one of the findings of a University of Michigan study of the diets and gut microbiomes of three Michigan coyote populations, published in the Journal of Animal Ecology.

The food-web study involved the genetic analysis of more than 350 carnivore scat samples—58 of which were confirmed as coyote scat—collected at three Michigan locations, one in the Upper Peninsula and two in the Lower Peninsula: the Huron Mountain Club in the U.P.; the University of Michigan Biological Station, at the northern tip of the Lower Peninsula near Pellston; and the Shiawassee National Wildlife Refuge near Saginaw.

The study also used photos from hundreds of motion-triggered wildlife cameras at the three sites to document local mammal populations, which include various coyote prey species. The camera network was established over the last several years by U-M wildlife ecologist Nyeema Harris, director of the Applied Wildlife Ecology Laboratory in the Department of Ecology and Evolutionary Biology and senior author of the new study.

“The co-occurrence of gray wolves and coyotes at the Huron Mountain Club may cause the  suppression of subordinate coyotes, forcing individuals to alter their consumption patterns and switch to alternate food sources,” said Harris, an assistant professor in the U-M Department of Ecology and Evolutionary Biology.

But at Lower Peninsula locations such as the Shiawassee National Wildlife Refuge, coyotes remain the top predator, with no observed pressure from gray wolves. These peninsular differences are reflected in the nitrogen-isotope ratios observed in the U-M scat study, said Shawn Colborn, the first author of the Journal of Animal Ecology paper.

The other authors of the study, in addition to Colborn and Harris, are Corbin Kuntze, a former U-M EEB master’s student and Gabriel Gadsden of U-M’s Applied Wildlife Ecology Lab and the Urban Energy Justice Lab at U-M’s School for Environment and Sustainability.

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