News

Return of the Fisher
by Tim McNulty

(Excerpted from the November 2001 issue of Forest Magazine)

A wood pewee breaks the silence of a warm June morning as I follow T. J. Catton down a forest slope in the Rogue River National Forest in southwest Oregon. Catton, a U.S. Forest Service wildlife researcher, stops midslope and homes in on his target with a handheld radio receiver. "She's within a hundred feet," he tells me, then climbs atop a large log for a clearer view.

The forest below us is undisturbed, an open, mixed-conifer stand of large Douglas-fir, white fir, sugar pine and the cinnamon-barked trunks of incense cedar. The steep slope bristles with standing snags and the ground is littered with fallen trees.

"There," Catton whispers, pointing to a large Douglas-fir snag eighty feet below us. I see a quick flash of dark eyes, and low, rounded ears peek around the tree. Then the lithe, catlike shape of a fisher walks unhurriedly out a mossy limb into full sunlight. Within seconds, she leaps gracefully to the limbs of a nearby hemlock and disappears.

She is a beautiful animal. Sunlight glistens over the deep brown-black fur of her shoulders and back. Her short legs and long, slender body mark her as a member of the weasel family, larger and darker than a pine marten, with a longer, stouter tail.

The fisher (Martes pennanti) has become extremely rare in West Coast forests. So rare, in fact, that biologists consider them extirpated from most of their Pacific range. But an ambitious research project is bringing these elusive hunters into the light.

Fishers are solitary, some would say secretive, hunters of deep forests. At one time, they held almost mythical renown for their prowess as predators on the ground or in the limbs of trees. "The marten can overtake the nimble red squirrel," wrote Victor Cahalane in his 1947 classic, Mammals of North America, "but the fisher can overtake the marten."

Fishers are consummate predators in mature forests, quick and efficient hunters of snowshoe hares, squirrels, small mammals and a variety of birds including jays, flickers and woodpeckers. As top-level carnivores, their effect on the forest ecosystem is profound. Fishers are the only predators that seek out and effectively hunt porcupines. They also feed on deer and elk carcasses, but their name is a misnomer: fishers do not fish.

Fishers once hunted the unbroken forests of North America from the Smoky Mountains in the Southeast to the pine and hardwood forests of New England and the Great Lakes states, across Canada to the vast conifer forests of British Columbia and south along the West Coast as far the Siskiyous and southern Sierra Nevada.

They made use of a wide range of forest types, denning in snags and hollow logs and resting on broad limbs and mistletoe brooms in the canopy. They were found at low and middle elevations (deep snow hampers their effectiveness as hunters). But fishers were never plentiful; they have the lowest population density of any terrestrial carnivores of their size.

Their fur, often compared to Russian sable, was prized for its deep luster. Through the nineteenth and early twentieth centuries, fishers were trapped relentlessly. Intense trapping was followed by widespread logging of the animals' habitats. Farms and residential developments replaced forests, and predator elimination programs took a severe toll. By the 1940s fishers had been eliminated from most of their range in the United States.

With the help of early trapping regulations, the abandonment of farms and the return of forests to the Northeast, eastern fishers rebounded. Populations were also assisted by reintroductions. Fishers' taste for porcupines put them in good standing with timber companies whose young plantations are frequently cropped by the spiny herbivores. Fishers were reintroduced to the northern Rockies, Michigan, Canada and parts of the Northeast largely by timber companies to control porcupine numbers.

Currently, the animals range across Canada, New England, the Adirondacks and the northern portions of Wisconsin and Minnesota. They also occur in the Clearwater region of northern Idaho. But despite more than sixty years of protection, they are found in only three small, isolated populations on the West Coast: the southern Sierra, the Klamath-Siskiyou region of the Oregon-California border and here, along the upper Rogue River in Oregon's southern Cascades.

The fisher we just spotted is one of nearly two dozen that have been radio collared over the course of a five-year study conducted by the U.S. Forest Service's research station in Olympia, Washington. Their movements, feeding and denning habits and reproductive success are closely monitored. This small population was reintroduced to the area in the late 1970s. What Catton and his fellow researchers are learning about the animals' use of their mixed-forest habitat will be invaluable for restoration of these little-known carnivores to their former Pacific range.

Keith Aubry is a research scientist with the Forest Service's research station in Olympia. He and wildlife biologist Cathy Raley direct the southern Oregon study. Aubry began surveying for fishers in western Washington in the late 1980s, and he has researched the record of fisher trappings and sightings in the state over the past century. His conclusion: fishers are extirpated statewide.

"I'd be hard-pressed to be convinced otherwise," he admits. "When you look at the Washington status report for fisher, there's not one single record by proven survey techniques."

Aubry began his Oregon study in 1995. A consortium of timber companies released fishers into the southern Oregon Cascades area from British Columbia between 1977 and 1981. None of the animals were radio collared or tagged for study.

"What interested me about this population was that they were introduced into an intensively managed landscape," Aubry says. "By studying the animals' habitat selection for den and rest sites in the forest, it gives us tremendous insights into how we might reintroduce fishers into other parts of their range."

Aubry points out that the mixed-conifer forests of southern Oregon were not clear-cut in the Northwest fashion but logged selectively. The result is an abundance of what biologists call "residual structure": large snags, downed trees and large live trees pocked with woodpecker cavities. "We're finding fishers using all these structures," Aubry reports. "That's why they have reestablished so well."

In an old-growth forest a few miles west of Crater Lake National Park, Cathy Raley points to a natal den in a large incense cedar. About thirty feet up the tree is a small pileated woodpecker hole where a collared female gave birth to a kit. Raley shows another natal den in a white pine snag not far away . "Natal dens are a critical habitat element," she explains. "The kits are born blind and naked, and they need a lot of protection." Entrance holes are small and allow females, but not males, which are twice their size, to pass. Further, den trees require heartwood decay, something rarely found in younger forests.

In eight weeks, kits are weaned and mobile but still dependent on their mothers for food. At that point, they are moved to a maternal den, generally a low cavity or hollow log on the forest floor, and will remain there for the next few months.

In five years, researchers have trapped and radio collared twenty-two fishers in the Oregon study. They located and described ten natal dens, nineteen maternal dens and more than 600 rest sites. Two-thirds of dens, one-half of rest sites and one-third of locations actively used by fishers were in "unmanaged" or old-growth forests. Raley and I also visited some heavily logged Boise Cascade land known to be used for foraging by a couple of males, but she says, "No adult reproductive females have been found in logged second growth."

Aubry and Raley will analyze their findings over the next year. Aubry is also working closely with biologists from Washington's Department of Fish and Wildlife to begin early planning for a possible reintroduction of fishers to Washington.* It's a lengthy process. Biologists will need to assess existing habitats to find which forest areas have recovered from earlyÐtwentieth century logging, a huge effort. They also have to design a radio-telemetry study for monitoring introduced animals. Then there's the question of obtaining animals for reintroduction.

"Ten years ago, I was against reintroduction," Aubry tells me. "I didn't think we had worked hard enough to determine whether fishers were extirpated from Washington." He didn't want to introduce genetic stock from outside the state until he had a better read on local populations. After a decade of surveys, he's convinced. There are no remnant populations to protect.

Under the best circumstances, returning fishers to Washington is still two or three years out. But Aubry remains optimistic about recovering fishers because it worked so well in Oregon. "Given the right forest conditions, there's no reason to believe fishers couldn't be restored throughout the Northwest."

Once they are, we will be an important step closer to returning our forests to ecological wholeness. As one biologist points out, "Top-level carnivores tend to have a big influence on ecosystems. Without the fisher, that role is missing from West Coast forests."