Three wildlife biologists swat at the forest undergrowth, still soaked from the morning’s summer thunderstorm, trekking deep into the woods until they find what they are looking for: a camera tied to a tree. They had set it up weeks ago to spy on the coyotes. A plane suddenly flies overhead, interrupting the tranquil hush of the forest. This is a New York City park, after all.
The camera traps are one of several methods the Gotham Coyote Project is using to track coyotes as they migrate into New York City, along with citizen science sightings, scat collection and now environmental DNA surveys. Mark Weckel, co-founder of the project, which is affiliated with the American Museum of Natural History (AMNH), estimates that at least 20 coyotes live in the city, most of them in the Bronx. But the wily animal is slowly claiming territory in Queens and Manhattan, as numerous news outlets reported this spring, ranging as far south as Battery Park at the tip of Lower Manhattan.
The spread of coyotes into New York City and other urban areas across the U.S. is the latest chapter in their impressive success story, says wildlife specialist Stan Gehrt of The Ohio State University, who has studied Chicago’s coyotes for more than 12 years. Government-sponsored poison initiatives in the 1970s and hunting programs that still exist today have killed millions of coyotes in the U.S. But the has species endured. Historically, the coyote never lived in the eastern U.S. but an opportunity arose in the late 1800s as people killed the gray wolf, the region’s native top predator, and deforested huge areas. As forests grew back and cities got greener, the coyote started to move into the apex predator position vacated by the wolf.
Long Island is one of the last remaining swaths of land in the continental U.S. for coyotes to colonize. It’s just a matter of time before the coyote moves in, says Coyote Project co-founder and Mianus River Gorge research director Chris Nagy, and the team will be there to study the invasion. It’s the kind of ideal before-and-after science experiment (pdf) that biologists rarely, if ever, get to conduct in nature. In the next year, Weckel says, the team will likely have the project up and running to study the environmental impacts coyotes will have on the ecosystems of Long Island as well as the social impacts the animals will have on people there.
In addition to camera traps, the researchers are using a new method to track the coyotes. In 2012 scientists from the Natural History Museum of Denmark identified different fish species just from the environmental DNA (eDNA) left behind in seawater. Since then, as sequencing technologies have become more and more powerful, eDNA has offered an attractive, noninvasive way to track animals. AMNH postdoctoral researcher Anthony Caragiulo collected soil samples from several Coyote Project camera sites and in the next few months will determine if eDNA will work for coyotes.
Observations of the Chicago coyotes suggest that their counterparts in New York City will do just fine. Gehrt uses radio collars on some of the coyotes in Chicago, which he says have shown him how easily they adapt to urban spaces. Coyotes travel along railroad tracks, bridges and even swim across lakes and rivers if they have to. They have now colonized downtown Chicago—one of the most developed areas in the country—and Gehrt says they’re actually showing positive population growth there. “We consistently underestimated them,” he says, “and we tend to put them in these nice envelopes or boundaries, which is really just a reflection of our limited understanding.”
Coyotes are territorial creatures, so they have a tendency of filling in all the space available to them over time. They mate for life, and the pups will usually stay with their parents for a couple years before setting off to claim territories of their own. Coyotes prefer to avoid humans at all costs, Weckel says. And diet studies have shown that when human food is available, coyotes actually choose to keep eating their natural fare of small mammals, fruit and insects. Gehrt says coyotes can provide crucial ecosystem services in cities by controlling explosive rodent populations—a welcome benefit for New Yorkers.
But in order for coyotes to successfully colonize cities, humans should let them be. Daniel Bogan, a behavioral ecologist at Siena College who has studied coyote–human interactions in New York State, says best practices include refraining from feeding coyotes so they don’t lose their wariness of humans, and keeping dogs on leashes so they don’t become a coyote’s next meal. “If there’s anything people should understand, [it] is that they should not live in fear of coyotes,” Bogan remarks. “They should take the proper precautions but they should not live in fear.”
After the morning of intense fieldwork in the woods the three scientists stopped for lunch at a Bronx diner. Weckel pulled out his laptop before he even checked the menu, flipping through hundreds of photos from the camera traps, searching for coyotes.
Suddenly pausing his lightning-fast photo survey, Weckel gasped. Nagy and Caragiulo leaned across the table to see his computer screen. It displayed a nighttime shot of a coyote standing directly in front of the camera with its head turned in a perfect silhouette. It was the first time they’d seen a coyote in the summer at that park in the South Bronx. “If you look somewhere long enough,” Nagy said with a smile, “you’ll find them.”