A coyote is outfitted with a GPS collar, which will be used to track its movements and predation patterns. Photo by Jacqueline Frair.
Coyotes have become ubiquitous in the Northeast since they began colonizing the region in the 1920s. The conventional wisdom has been that coyotes are specialists in preying on deer, thus filling a biological niche left by the extirpated wolves. But new research by scientists at the SUNY College of Environmental Science and Forestry indicates that this is no longer the case and may never have been, at least in the Adirondack Mountain region.
Using archived coyote scat and data from past studies, Jacqueline Frair and her colleagues constructed a timeline of coyote diets in the Adirondacks going as far back as the 1950s. They also walked trails and collected fresh coyote scat to identify their present prey.
The researchers found that the primary prey of coyotes in the Adirondacks historically was snowshoe hare, and in recent years it has been mostly beaver, whose populations are more stable from year to year than those of the hare. Deer were a primary resource only when those species were less available. “They seemed to augment their diet with deer when hare were in a down cycle, and now they’ve switched to beaver,” Frair said. “Coyotes can certainly take a deer, but a nice fat beaver seems to be preferred.”
In the Adirondacks, coyotes primarily kill adult deer in winter, when the snow is deep. But their consumption of deer in winter declined from the 1980s to the present, so Frair doesn’t believe coyotes are having a significant effect on adult deer mortality. Coyotes’ consumption of fawns during that period remained consistent.
The big question is how coyotes’ consumption of beaver will affect deer. “By concentrating on the abundant beaver, coyotes may ultimately lower their overall use of deer,” she said. “Or it may elevate the population of coyotes and have a spillover effect on deer. Time will tell.”
Outside of the Adirondacks, however, Frair thinks coyotes have little effect on deer. In the southern tier of New York, where she conducted a comparative study, most of the deer consumed by coyotes were shown to be scavenged; there, coyotes’ primary prey was cottontails, woodchucks, livestock, and small mammals like squirrels.
In a related study, Frair found that the abundant coyotes in the Adirondack region are directly competing for prey with other native carnivores, especially gray and red foxes, bobcats, and fishers. She speculates that coyotes may be displacing fishers in parts of northern New York. And though their diets largely overlap, Frair said that red foxes are finding a refuge from coyote competition by spending more time in suburban backyards. Her next studies will examine how coyotes interact with red foxes, especially in human-dominated landscapes.