Pacific fisher study begins
To catch a predator: ODFW begins study on the different populations of the small Pacific fisher
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State wildlife biologists are heading into the recesses of the Rogue Valley to capture a little DNA from a rare and elusive backwoods weasel so predatory it will gladly eat every porcupine it can get its mitts on.
The Oregon Department of Fish and Wildlife on Friday began a three-year study on the genetic make-up of Pacific fishers believed to be living in isolated pockets of forest habitat in the Siskiyou and Cascade ranges.
PACIFIC FISHER
(Martes pennanti)
What: A cousin of weasels and pine martens.
Description: Up to 2 feet long and 20 pounds, with males larger than females. Fur ranges from medium to dark brown, with gold to silver on the head and shoulders, black legs and tail. They may have a cream-colored chest.
Unique characteristics: All have five toes with retractable claws. Only animal known to prey regularly on porcupines.
Diet: Hunting alone, they normally eat mice, squirrels, hares, birds and shrews.
Habits: Agile and speedy tree climbers, they are rarely seen by humans. Prefer mid- to high-elevation mixed-conifer stands. Communicate to each other by leaving scent markings.
Local population: The U.S. Forest Service has no estimate of the local population, but other federal studies estimate 1,000 to 2,000 animals in Northern California.
The Siskiyou Mountains hold a remnant population of native fishers, while the Cascades of eastern Jackson County are home to a group created when animals from Minnesota were introduced there in the 1960s.
Biologists are hoping remote-sensored cameras hidden in canyon oak stands well outside of the town of Rogue River will capture pictures of the 20-pound predators.
But the main targets are small tuffs of fisher hair — key evidence to determine if the two fisher populations remain isolated from each other or whether some of the weasels have crossed Interstate 5 and interbred.
"If we find any fishers here, we'd expect them to be from the native population," says ODFW Rogue District wildlife biologist Mark Vargas, as he fashions the remote "game cam" camera to a madrone.
"If not, to know if there has been some interbreeding would be interesting," Vargas says.
The study seeks to sample fisher hair from both the native and the introduced populations over the next three winters, Vargas says.
They will sample fishers within mid-elevation habitat primarily on private lands and federal Bureau of Land Management lands, Vargas says. The data will be added to decades' worth of studies done by BLM and Forest Service biologists on local fishers, which remain a candidate for listing under the federal Endangered Species Act.
Dave Clayton, a Forest Service biologist who has studied local fishers for years, says any hybrid fishers would be treated as a single population, as the native and introduced groups are now.
A conservation assessment and strategy for fishers is due out later this year, and any information from the state study will help shine light on a group of animals so reclusive that Clayton says no decent population estimate exists.
"This will help us look at the big picture in terms of how to manage this species," Clayton says.
About the size of a fat house cat, Pacific fishers are true forest predators. Fast, agile and adept at climbing trees, fishers eat any prey they can overpower, including squirrels, hares, mice and birds. They also are the only known animal to prey regularly on porcupines — they repeatedly bat the porcupine until it is stunned, "then they go for the soft underbelly," Vargas says.
Historically ranging in forests throughout Western Washington, Western Oregon and Northern California, fishers are no longer found in more than 80 percent of their former range, according to the U.S. Fish and Wildlife Service.
Fishers often are mistaken for a smaller cousin called the pine marten, which are more common and found more regularly at higher elevations, Clayton says.
Trappers and others who venture regularly into the woods have reported seeing fishers in the Siskiyous of Jackson County, says ODFW biologist Steve Niemela, who stumbled across a fisher himself while looking for a radio-transmitting deer collar last spring.
A wood rat apparently found the collar and dragged it to its nest high in a tree, Niemela says. Niemela mounted a remote camera pointed at the nest in hopes of garnering footage of the wood rat.
Instead, he captured a short video of a fisher pouncing into the nest in search of a quick meal.
"It was pretty amazing," Niemela says.
Finding fishers when you're actually looking for them, however, is more difficult.
Niemela and Vargas on Thursday scouted for a sampling site, settling on a dense patch of canyon oak on BLM land at about the 3,500-foot elevation level, far off a spur road.
Niemela placed a long, handmade, trap-like box opened on one side. Over the opening are two wooden slats onto which sticky tape is affixed.
The trap was baited with the head of a rotting steelhead and a pile of lichen laced with various scents and odors. A wire-mesh bag of more steelhead meat was suspended overhead by a chord strung between two trees.
Collectively, the odors roll out an aerial chum-line for furry critters great and small.
"This is to get them coming from a long ways away," Vargas says. "Who knows what we'll attract? We're hoping for fishers, but a lot more than fishers lurk in this area."
The idea is to entice the fisher to crawl into the box for the bait, then escape. When it does, the tape will snare a few fibers of hair, which will be sent to a lab for DNA testing.
The camera is trained onto the trap to snap an image of whatever critter crawls into the trap. That way, Vargas says, biologists can collect hair samples only from animals identified as fishers.
The ODFW this year will set six traps, which they plan to check and rebait weekly until early March, Vargas says.
"I'm optimistic we're going to catch something," Vargas says.
Vargas has sought a private grant to buy 18 more cameras to expand the test scope to 24 sites for 2011 and 2012, he says.
Reach reporter Mark Freeman at 776-4470 or e-mail at mfreeman@mailtribune.com.
