Cameras and sensors document Tahoe’s little critters
RENO (AP) — Road kill, smelly stuff, light sensors and remote automatic cameras are being used to document small, furry critters that make their home around the Lake Tahoe Basin.
A $40,000 federally funded study being conducted by the Nevada Division of Wildlife is a tiny part of the $900 million Tahoe Environmental Improvement Project, an ambitious plan of programs and environmental measures researchers say are needed to protect Lake Tahoe’s famed clarity and the basin’s delicately balanced ecosystem.
While erosion control, water quality and air quality are the big-ticket items of the improvement plan, wildlife, fisheries, recreation and scenic resources also were included as important to the Tahoe area’s overall environmental stability.
The Division of Wildlife study focuses on small furbearers — martens, fishers, mink, bobcats, short- and long-tail weasels and wolverines.
“There has never been anything but cursory surveys for these furbearers in the past,” said Shawn Espinosa, the Division of Wildlife biologist leading the study. “It’s the most extensive on the east side of Lake Tahoe that’s ever been done.”
Finding the animals, however, is not easy.
“They’re pretty secretive,” said Jenni Jeffers, another biologist involved in the study.
Most are nocturnal. Some, such as martens, often hunt for their food while burrowing under the snow.
“You’ll see a rabbit and all of a sudden it disappears under the snow,” Jeffers said.
Researchers are counting on the stealth of modern technology combined with the primal attraction of food and luring scents to document the animals.
In late January, the biologists and about 10 volunteers suspended wire baskets stuffed with deer meat — roadkill victims of Nevada roads — from trees at 12 different sites in Lake Tahoe Nevada State Park. The 14,500-acre, densely forested park includes the areas around Spooner and Marlette lakes east to Washoe Valley near Carson City, and Sand Harbor.
A concoction of smelly stuff — skunk oil, fish oil and other nasty scents — were added to the mix to make the meal even more enticing.
Battery-operated light sensors hung from trees near the bait stations were connected to automatic cameras. In a wildlife version of “Candid Camera,” an animal lured to the feast will break the light beam from the sensor, triggering the camera.
The volunteers use a snowmobile to get to the remote sites, but must snowshoe or cross-country the final legs. They check the bait and cameras once a week for about a month.
After the first two weeks, the only pictures were of flying squirrels, Espinosa said.
But biologists were encouraged by an empty bait cage and tracks believed to belong to a marten. Unfortunately, the cable connecting the sensor to the camera had fallen off, so there was no film evidence.
“We think the last wind storm we had knocked a camera loose,” he said. The equipment was reattached and new meat was baited.
The study is being conducted in winter to try to avoid interference from furbearers of a larger sort — bears.
“Hopefully all the bears are asleep and won’t be messing with our cameras and bait,” Jeffers said.
If furbearers are detected, the second phase of the study will involve trapping the animals and putting radio collars on them to track their movements, Espinosa said.
If no animal are detected, the stations will be moved to other locations.
Previous surveys in the past decade have detected marten and bobcats in several areas around the Lake Tahoe Basin, said Mollie Hurt, a biologist with the U.S. Forest Service’s Lake Tahoe Management Unit.
Fishers are another matter.
“There are no recent reliable detections of fisher in the Lake Tahoe Basin,” she said.
That would make capturing one on film all the more exciting, Espinosa and Jeffers said.
“They haven’t been seen up here in a while,” Jeffers said. “It’d be really neat to get a picture of a fisher or a wolverine.”
Wolverine sightings in the Sierra Nevada have been incidental at best over the past decade. The last one in the Lake Tahoe Basin was observed by a wildlife biologist near Emerald Bay in 1990, Hurt said.
Espinosa said results of the survey will help in habitat management and planning.