Science

Grand Teton National Park tries to understand crafty foxes

Posted August 30

— John Stephenson stood atop a boulder in a steep talus field high above Jenny Lake, turning a VHF tracking antenna from side to side.

To a layman the fuzzy beeps that bounced back sounded like a whole lot of nothing. To the Grand Teton National Park wildlife biologist, they told the tale of a red fox out of sight and on the move.

"It's not here," Stephenson said on an early August Friday. "They do move."

The female fox Stephenson was after, he suspected, had a litter, though the kits had not been verified. The wildlife biologist's fox hunt, enabled by a batch of very-high-frequency GPS collars that went out last winter, is part of a multiyear project to boost what's known about a population of Vulpes vulpes that's thought to be swelling in size and adapting to people.

"Over the last 30 years," Stephenson said, "we're seeing more and more den sites and encroachment into developed areas."

Put a smart, notoriously curious species near people and human food, and habituation is bound to occur. In Teton Park that human-canine clash has manifested itself in foxes posting up near ice fishing holes on Jackson Lake, waiting for meals of lake trout guts. There have even been reports of foxes taking a cue from bad-behaving dogs and jumping up onto people to try to swipe a meal out of hand.

An "unfortunate reality," Stephenson said, is that foxes exhibiting such bold behavior may have to be euthanized in the future.

"That's a worst-case scenario," he said, "but it definitely is a possible outcome."

Nine foxes have been fitted with tracking equipment at Moose, at Teton Science Schools' Kelly campus and near Signal Mountain. Three more research animals were sought in the Colter Bay area, but the foxes outsmarted park wildlife crews, thanks partly to trap-triggering pine martens.

In the early going Stephenson is starting to accumulate information about the species' movements and distribution in Jackson Hole. There have been reports of foxes in the Tetons as high as Marion Lake, at 10,450 feet. One animal marked near Moose wound up dead in the Flat Creek bog just north of Jackson, likely the casualty of a vehicle strike on Highway 89. Two others have died, both of unknown causes.

Another goal is to learn what omnivorous foxes are eating.

Anecdotally, there have been observations of foxes keying in on ground squirrels in the sagebrush on the east side of the park. A Teton Park visitor once turned in a photo of a "wolf pup," actually a black-color-phased fox, carrying around a marmot in Cascade Canyon. Remote cameras set up at den sites will help with the diet analysis, as will isotope analysis of fox hair from road-killed and captured animals.

So far, encouragingly, none of the park's research foxes has been making a living on fishermen's gut piles or PB&Js.

"Certainly some are sticking around developed areas," Stephenson said, "but even those are doing wild, natural fox stuff."

After striking out on a couple of sighting attempts on Aug. 4, he climbed higher to try to circle above his research specimen. But the fox scurrying through the rock field above Jenny Lake stayed on the go, and he never did lay eyes on the critter.

"Outfoxed, again," Stephenson quipped, phony British accent included.

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