Getting to the bottom of gray fox decline

Their population is declining in the Midwest, so scientists are extremely interested in sightings of the gray fox. But the furry canid is elusive, if not reclusive, making it difficult to get hard and fast numbers. On top of that, they can climb trees.

In his previous career, Jonathon Cepek, wildlife ecologist for the Cleveland Metroparks, used to see gray fox fairly often on his way to work near Sandusky. Once, he spotted a specimen of the distinctive furbearer in a tree.

“That was probably 20 years ago,” he said. In the 10 years he has been with Cleveland Metroparks, sightings have been few and far between.

In 2015, more than 200 cameras were deployed throughout the 24,000 acres of parks that span six counties. Though 90% of the cameras record coyotes and 50% snap red fox on a regular basis, there have been only three gray fox captured digitally: two in 2016 and one in 2019.

Tree climbers

Cepek wonders if their tree-climbing ability may contribute to the low number of sightings. After all, trail cams aren’t pointed at the canopy, and folks hunting or doing wildlife surveys aren’t likely to look up.

“Their claws are partially retractable, similar to a cat’s, so they climb trees roughly the same way that cats do,” said Katie Dennison, wildlife biologist with the Ohio Division of Wildlife, whose main responsibility is monitoring, research and management of Ohio’s 16 furbearer species.

Scientists think they climb trees to escape threats, like larger predators, or perhaps to sun themselves on a chilly day. But it also could be because of diet, Dennison said. Like their red relatives, gray foxes are omnivores. They eat mice, shrews, cottontail rabbits, birds and occasionally insects for protein.

But at certain times of year, fruits, nuts and seeds make up between 30 and 50% of the gray fox’s diet — much more than that of the red fox or other canid species.

“One theory is that they climb trees so they can forage for nuts and fruit,” Dennison said.

In decline

Like many other species, the gray fox’s distribution in Ohio declined in the early- to mid- 1800s but began to rebound in the early 1900s. However, their population has declined in the past 30 years to the point that it was recently declared a “species of concern” on Ohio’s list of endangered and threatened species.

Ron Ferenchak, Grand River Wildlife Area supervisor, has seen that firsthand. Fresh out of college in the 1990s, he and his friends could see six to 10 gray fox per night when they went hunting in Southeast Ohio. Though they were not as plentiful in the northeast, probably 40% of the foxes they saw in Ashtabula County were gray, he said. In the last 15 or 20 years, the numbers of red fox — and coyote — in that area have grown considerably, while gray fox sightings”have been pretty non-existent,” Ferenchak said.

Allen County Wildlife Officer Craig Barr has seen a similar trend in Northwest Ohio. He hears stories from trappers that gray fox once outnumbered red in their harvests. But the number of sightings in the past 10 years can probably be counted on one hand, and there have been no reports in the past three years, he said.

Southeast Ohio has the most forested acres in the state, and also the most sightings of gray fox. Though they are sometimes seen in brushy or edge habitats, the cover provided by thick forests seems to be important to the gray fox, while red fox have adapted to agricultural and even suburban settings, Dennison said. Yet even in the densely forested hills of Athens County, sightings of gray fox are rare.

Lindsey Rist, communications specialist for Division of Wildlife District 4, has only seen a few footprints in the snow, and one running along the road as she was driving to work. On a mid-October morning five years ago, she found a gray fox sleeping in the middle of the road and “gently nudged it out of the way,” she said.

Causes

The increase in coyotes and the decrease in gray fox in Ohio is probably not coincidental. Coyotes prey on both gray and red fox, not only as food, but because they see them as competitors.

“Sometimes, they just kill them and leave them,” said Suzanne Prange, founder, executive director and lead scientist at the Appalachian Wildlife Research Institute. “Although in this case, the gray fox seems to have an advantage over the red because they can climb trees to escape.”

But the gray fox in Ohio can’t seem to escape canine distemper. They get the disease from both coyotes and raccoons, whose numbers have also increased exponentially in the state. That’s one of the reasons Prange is making gray fox her primary focus these days. She and other scientists are concerned that their low numbers have led to too much inbreeding, which in turn may have weakened their immune systems.

Research

Several years ago, Prange participated in a pilot study aimed at putting radio collars on gray fox in 20 counties in Southeast Ohio. Unfortunately, they were only able to find 15 specimens to collar in that entire area, and within a year, 11 of them had died. Most died from canine distemper, but some died of infections from very minor injuries.

“These were injuries that shouldn’t have been a problem,” she said. “To develop a massive infection over a tiny cut is indicative of immune deficiency.”

In 2019 and 2020, Prange and the institute, a non-profit based in Athens, paid trappers for gray fox specimens so that Christine Anderson and her students in the Biological and Environmental Science department at Capital University could do DNA analysis.

Because more genetic research is needed, the institute is raising funds to buy cameras to put in the southern and eastern counties of the Appalachian Plateau. If they can locate “pockets” of gray fox, researchers can do more DNA testing to find out if their theory about inbreeding and its effect on the immune system is correct. If it is, Prange and others hope a solution can be found, perhaps by transporting gray fox from other parts of the state.

“Gray fox are doing fine in western states, so they’re not threatened with extinction,” Prange said. “But it would be a shame to lose them from Ohio and other midwestern states if we can do something to fix the problem.”

The gray fox is the only canid that is truly native to Ohio and is considered an ancient species, much older than red fox or other canids, including the domestic dog, she said. Scientists say there is evidence of gray fox and its closest relative, the island fox, living in North America for two million years.

Surprisingly, the red fox is in a different genus than the gray, along with the Arctic fox, kit fox and swift fox. Scientists say they were present in North America, but only in the northernmost reaches of what is now Canada and the western United States. They didn’t appear to be in Ohio until the arrival of European settlers, who may have brought the red fox with them to hunt.

Citizen science

The numbers that we do have for gray fox in the state come from citizen science by some of Ohio’s bow hunters. Back in 1990, the Division of Wildlife started the Ohio Bowhunter Survey to track changes in furbearer populations as well as record sightings of black bears, river otters and other species of interest.

Volunteers do the survey between the opening day of deer archery season and the first day of deer gun season. They record the time they spend hunting each day, the species seen, and the county where they were spotted. Later, wildlife staff turn the sightings into the “bowhunter index,” or the number of each species seen for every 1,000 hours spent hunting. This way, the numbers are standardized and can give biologists a way to track changes in populations over time.

In the early 1990s, between five and six gray foxes were spotted per 1,000 hours of hunting. Last year, the number was only 2.6.

“Gray fox are a unique species and an important part of our ecosystems,” Dennison said. “The apparent decline in their population is a concern, and something that we’re monitoring closely.”

If you are lucky enough to see a gray fox, either in a tree or on the ground, you can report it by going on Wildohio.gov and clicking on “Report Wildlife Sightings.” Those interested in becoming part of the bowhunters survey can email Dennison at Catherine.Dennison@dnr.ohio.gov.