At the beginning of my junior year at NC State, I caught a city bus downtown to the North Carolina Museum of Natural Sciences. I had a meeting with Biodiversity Lab Director Roland Kays to discuss undergraduate research opportunities. I had no idea what “undergraduate research” meant.
After a brief discussion in which Dr. Kays learned that I hadn’t a clue what I wanted to study, he said, “Can you start today?”
The Biodiversity Lab has one entire wall, which is in fact a window allowing the public to view the lab goings-on as they stroll through the museum. I sat down that day in front of said window with a plate of scat. A plate of poop. Coyote poop, to be exact.
For the rest of the semester, I held a volunteer position in the lab sorting coyote scat. The poop sorting was part of an NC State research project to study food habits of coyotes at Fort Bragg Military Installation in the southeastern part of the state. Scat is a relatively common method used to determine the diets of predator species and we’ve been using that reliable method for a long time.
Do you remember dissecting owl pellets in grade school? They were filled with hair and bones—the bits of prey that owls can’t digest. Owls spit out those indigestible pieces, but coyotes let the digestive system take care of them. Coyotes swallow their entire food item and anything that can’t be digested is pushed through the digestive tract and out the other end. Some of those leftover bits turn out to be identifiable teeth, fur, feathers, insects, and seeds. That’s what scatologists are after.
Getting to those identifiable items is actually quite simple. In this study, researchers collected coyote scat by gathering up samples they spotted along roads at the study site. Back at the lab, they rinsed the samples through mesh sieves, which collected the large, important parts of the scat, like clumps of hair and bones, and allowed the rest of the sample to wash away.
Then came the sorting (i.e., the reason I came to the lab each week). I picked apart samples and created like piles of diet items. Some samples consisted strictly of hair and bones while others were made up primarily of seeds. I even found garbage like candy wrappers and paracord (remember the study was conducted on Fort Bragg) in some samples.
The next and final step is identifying all of those piles of diet items. Researchers used species-specific patterns visible in prey hairs under a microscope to identify the hair masses found in scats. Likewise, mammal teeth were identifiable with a trusty guidebook. Researchers also identified plant seeds to species and insects to order when possible and created more general categories in the data for items like garbage and birds.
The final data set paints a picture of what coyotes at Fort Bragg are eating. One scat can’t tell the whole story; scientists must go through the finding, washing, sorting, and identifying process for many samples to discover what coyotes are really eating out there.
As it turns out, coyotes at Fort Bragg commonly consumed fruits, mammals, and insects. Diet shifted depending on season, which reflects a shift in food availabilities. Coyotes took advantage of plentiful persimmon fruits in fall and insects in spring when warmer weather triggers young grasshoppers, crickets, and other insects to emerge from their eggs. White-tailed deer were the most commonly depredated mammal. NC State master’s student Morgan Swingen summarizes the data in a science paper published in the journal Southeastern Naturalist.
I am glad I sat down in front of that window-wall with a plate of scat back in undergrad. That volunteer position in the lab led to some other exciting scat research down the road. Stay tuned to my Scoop on Poop series for more on how researchers are using scat to learn about our wildlife!