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GPS study should provide info on bobcats’ home ranges, researchers say

January 23, 2019
Most of the bobcats collared by biologists Rich Rogers, left, and Kirsten Belcher weigh between 13 and 20 pounds. Females tend to be considerably smaller than males.

Somewhere in West Virginia’s eastern highlands prowl some seriously tuned-in bobcats.

Each of the cats wears a collar that, every 5 hours, transmits the animal’s location to a satellite orbiting overhead. At the click of a computer mouse, researchers can see how far each cat moves within its home range.

The idea is to learn how much territory a bobcat needs to make a living, and what kind of habitat it prefers. Kirsten Belcher, the West Virginia University graduate student doing the research, said the three-year study got started in early November, when the state’s bobcat-trapping season began.

“We’re asking trappers to live-trap bobcats for us so we can put [Global Positioning System] collars on them,” Belcher explained. “So far, we have eight. Our goal is to get collars on 30 this year and 30 more next year. We’re shooting for a 50-50 split between males and females.”

The study — a cooperative effort by the state Division of Natural Resources and WVU — will encompass the entire Eastern Panhandle plus the highland counties of Tucker, Randolph and Pocahontas.

“All in all, 11 counties are involved,” Belcher said. “That gives us two ecological regions to look at, one of which is more productive for bobcat harvest than the other.”

Knowing the extent of the animals’ home ranges will ultimately help biologists refine the computer models they use to estimate population densities. Knowing how many cats are out there will allow DNR officials to establish hunting-and trapping-harvest limits that keep the population in balance with its habitat.

Currently, that limit is three per season for each hunter or trapper. Rich Rogers, the DNR’s furbearer project leader, said trappers have been asking for a higher limit since the price of bobcat pelts went up a few years back.

“Before we can increase the bag limit, we first have to make sure a harvest increase won’t result in us taking so many animals that we end up depressing the population,” Rogers said.

DNR officials recently completed a study that involved collecting bobcat fur from “hair snares” that snagged the fur of cats lured to baited enclosures. By examining the DNA from each fur sample, researchers were able to determine how many bobcats were visiting the traps and extrapolate from that approximately how many were present in the area.

At the same time the hairsnare project was taking place, other researchers were examining bobcat carcasses to determine reproduction and mortality rates.

Rogers said those two studies appeared to indicate that hunters and trappers already were taking enough cats to keep the population in check.

“It also indicated that we’re near the upper limit of what we can sustain with the bag limit we have,” he added. “If this [GPS] study shows that bobcats’ home ranges are smaller than we believe they are, we might change the limit.”

Completing the study will depend, in part, on how many bobcats trappers are willing to live-trap and release. Chris Ryan, the DNR’s head of game management services, said there’s a pretty strong reward for doing so.

“We’re paying a $100 reward for every cat caught safe, collared and released,” he continued. “That’s more than a pelt is worth. Trappers who wish to help with the study should contact our Romney office at 304-822-3551.”

Trapping activity usually picks up in January and February, and Belcher expects to put collars on many more bobcats before the season’s Feb. 28 close.

“The collars’ batteries last two years,” she said. “So if we get 30 collars out there this year and 30 next year, we’ll be able to study each cat for two years before the study ends.”

The collars are small, just 350 grams. Belcher said they need to be, because bobcats aren’t as large as many folks think.

“All the females we’ve caught so far weighed between 12 and 13 1/2 pounds,” she continued. “The males have ranged between 18 1/2 and 20 1/2 pounds. We keep the collars small and light so they don’t affect the animals’ behavior.”

The collars’ GPS units uplink the cats’ locations every 5 hours. Every 48 hours, the satellite downlinks the information to Belcher’s computer.

“The computer connects the dots,” she said. “We’ll be able to see the home ranges of males and females. We’ll also see what kind of habitat they select, and from that we might be able to determine why one habitat is favored over another.

“We expect to see some changes in movement from season to season. For example, we expect females to move less while they’re raising young. During the breeding season, we expect to see males moving more as they try to find mates.”

Eventually, Belcher said, DNR officials hope to study bobcat survival.

“Right now, we don’t know what the cause of natural mortality is for these animals,” she explained. “The only metric so far is harvest, from hunting or trapping. We’d like to find out what the other causes of mortality are.”

Animal-rights activists are pushing federal and state regulators to outlaw the hunting and trapping of all cats, including bobcats. Rogers said data gathered during previous and current studies should help to keep that from taking place.

“Right now, [activists] are attacking the federal government, saying the feds violated the National Environmental Policy act in regard to the [United Nations Convention on International Trade of Endangered Species],” he said. “We have data that show we have plenty of cats, and we’ll share that data with other states.”

According to the Winter 2018-19 Furbearer Management Newsletter issued by the DNR, West Virginia is home to approximately 9,549 individual bobcats, which Rogers said is “a healthy population.”

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