"Stormy" wolverine photographed in Eagle Cap wilderness in 2011. Courtesy Audrey Magoun.
Biologists seek first photo evidence of species in western Oregon
Some will tell you it's a pygmy variety of bear. To others, it's a superhero with fierce sideburns. On the spectrum of enigmatic beasts, it's only slightly less mysterious than a sasquatch. But the wolverine is a very real animal, and biologists want to know whether the species is living in Oregon's Cascade Mountains.
"Everyone agrees that the wilderness around the Three Sisters, Mount Washington and Mount Jefferson contain wolverine habitat," said Jamie McFadden, biologist and project leader with Oregon Wildlife. "But there's never been any photographic evidence of them from that area."
The wolverine — a 40-pound, tough-as-nails member of the weasel family — is naturally uncommon throughout its range. Between 1921 and 2000, fewer than 10 verified sightings were recorded in Oregon.
McFadden hopes her remote camera-trap survey, an Oregon Department of Fish and Wildlife project funded in part by the Oregon Zoo's Future for Wildlife grant program, will yield the first documentation of this rare creature in Oregon's Cascade Range.
"The wolverine has a state status as threatened, and it's a federal candidate under the Endangered Species Act," McFadden said. "We're hoping this study will help inform state and federal wildlife management agencies for decisions about wolverine and forest carnivore conservation efforts."
Nobody knows whether wolverines breed in Oregon, but in 2008, one was camera-trapped in Northern California. DNA from a hair sample it left behind suggested the animal was from Idaho.
Then, in 2011, biologist Audrey Magoun captured Oregon's first wolverine photos during her camera-trap survey in the northeast corner of the state. DNA from one of those animals also suggested an Idaho lineage.
"Are the wolverines using Oregon as a dispersal corridor, or do some actually live here?" McFadden asked. "That's one question that we're trying to answer."
Adult male wolverines lay claim to a home range of about 350 square miles — the equivalent of one person occupying all of San Francisco and Oakland. Young animals in search of their home turf cover even more ground.
"We radio-collared one sub-adult in Montana that roamed an area of about 14,300 square miles," Dr. Magoun said.
"We now have a pretty sophisticated camera-trap system," McFadden said. "We can coax a wolverine into taking a picture of itself while striking a certain pose that reveals its identity and sex — and even, if it's a female, whether it's lactating during the spring months."
A lactating female means kits are nearby, and finding one is the only way scientists can prove that Oregon has home-grown wolverines. But capturing photos of any wolverine — lactating or not — is a challenging affair.
"It involves snowshoeing uphill through miles of dangerous avalanche country while wearing a heavy backpack," Magoun said. "Wolverines don't make it easy. That's probably why they've lasted so long."
First, McFadden and her team members will find a spot with two trees spread about 10 feet apart. They'll run a cable to which they attach the bait — typically a slab of road-killed deer.
"An animal carcass is like a dream come true for scavenging wolverines," McFadden said. "When we see a road-killed deer, we often pick it up. This requires a special permit from ODFW."
Because wolverines are extremely tenacious, the team must drill a hole through a bone in the carcass to use as the attachment point.
That also helps keep other predators, such as black bears, from pulling it down prematurely.
The team then installs a platform just tall enough for a wolverine to climb and access the bait. When it reaches up, it exposes the unique pattern of cream-colored spots on its chin and chest — a sort of wolverine fingerprint.
Aiming at the whole setup is a camera that takes a picture whenever it detects movement.
The system can also reveal a wandering wolverine's hometown. The furry beast must squeeze through a gauntlet of spring-loaded hair-snag clips in order to reach the bait.
"If a viable hair sample is collected, the DNA can be compared against a library to determine whether a wolverine may have come from Idaho or Washington or elsewhere," McFadden said.
McFadden and her project team began deploying camera traps in October and plan to check them every three to six weeks. If any wolverines are photographed, those cameras will be checked more frequently.
"This is a particularly exciting and important project," said Dr. David Shepherdson, deputy conservation manager with the Oregon Zoo. "Managing for carnivores provides wildlife linkages between habitats that can be used by other species."
McFadden also hopes her camera traps will collect critical data on other sensitive species, such as American marten and montane red fox. Even if she finds no wolverines, she will have successfully conducted the first systematic photographic wolverine survey in Oregon's Cascades.
"Nobody thought we'd find them in the Wallowas, but we did," Magoun said. "If Jamie finds wolverines in the Cascades, so close to a large human population, it will be way bigger news."