What, Exactly, Are Southern California’s Coyotes Eating?
Piles of poop are helping researchers dissect the diet of urban and suburban canids.
Again and again and again, the volunteers went looking for poop. They tromped through cemeteries and parks, hugged the fence line, and wandered paved and dirt roads in search of links about the size of their thumbs, with tapered ends. They avoided smaller nuggets—no thanks, opossums—and ones with rounded tips, which suggested they’d been dropped by a bobcat. These poop scouts were scouring Los Angeles and the Conejo Valley in search of hints about coyotes’ palates.
For several years, biologists have kept track of the canids moving around Southern California’s cities and suburbs. Researchers have tracked them with GPS collars and camera traps, and confirmed that they’ve been chowing down—but they haven’t gotten a full picture of all the meals coyotes are consuming.
“You hear a lot of different things, like, ‘Oh, they’re living off of rats, my neighbor’s feeding them, they’re only living off of cats in the neighborhood,” says Justin Brown, an ecologist at the National Park Service’s Santa Monica Mountains National Recreation Area. “People had a wide variety of thoughts.” To get a better picture of how the coyotes were flourishing in these urban and suburban enclaves, “you need to know what resources they’re using,” Brown says. Food is fuel, and the proof’s in the poop.
For the past two years, Brown has led a project to collect coyote scat around the Conejo Valley, including Thousand Oaks, and compare it to samples collected in denser, busier Los Angeles. “Our goal was to look at urban to suburban gradient, and see how that affects their diet,” Brown says.
After a crash course in scat identification, volunteers fanned out to their assigned sites (27 in L.A., and 14 in Thousand Oaks), and looked for poop that fit the bill. To distinguish the coyote poop from piles left by domestic dogs, they only collected samples that had visible evidence of bone, hair, or fruit seeds—unlike Fido, coyotes eat their dinner whole. They plopped the piles into paper bags. Back in the lab, researchers put them in pantyhose and ran them through the washer and dryer to clean them up and help make it easier to isolate and identify the bones, seeds, and other components inside. They also baked the poop, to kill parasites.
Coyotes tend to trod the same territory again and again, Brown says, so it’s likely that scat collected from the same site over time is shedding light on the behavior of the same individuals from one season to another. (It’s a more complete picture than, say, a stomach necropsy, which only gives a glimpse of the animal’s last meal—though the team did some of those, too.)
Still, scat’s not a perfect portal into the animals’ meals. Human food—such as burgers and bread—doesn’t tend to show up in the poop “unless the coyotes eat the wrapper,” Brown says, because our grub is more fully digestible than bone or tufts of hair. The team did find evidence of work gloves, a condom, shoe laces, and plenty of packaging. Whiskers provided a clue about how and when the animals were consuming the food intended for us and our pets. By snipping these into segments and performing stable isotope analysis—looking for ratios of carbon and nitrogen—researchers could gauge whether the animals had eaten corn, for instance, and how that had changed over time (give or take a few weeks).
By early April 2019, they expect to be done with dissections—more than 3,200 in all. Then the team will tidy up the data and start submitting it to scientific journals. Based on their findings so far, it seems that the coyotes of Los Angeles are feasting on food for humans and pets, plus pets themselves (especially domestic cats), and fruit from ornamental trees, such as figs. The scat from Thousand Oaks indicates that the coyotes with more green space to roam around are noshing primarily on rabbits, followed by fruits, gophers, and insects.
Over the past few years, the relationship between Southern California’s humans and their canid neighbors has been more than a little strained. There have been several reports of coyotes eating family pets or biting people; humans, meanwhile, have occasionally taken out a coyote with a gun, and packed city council meetings wearing shirts calling on officials to evict the animals from their towns. Meanwhile, researchers have found that “a lot of [coyotes] are living pretty much everywhere, and a lot of them aren’t causing conflicts,” Brown says. Where they’re unwelcome, he adds, “we can control the food sources,” whether those are trees, or a buffet of offerings from overflowing trash cans. Some residents will surely think it’s not enough, but decoding the poop is one place to start.
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