A Tale of Three Weasels

How biologists are trying to ensure that wolverines, fishers, and martens have a future in Washington.

WILDLIFE SIGHTINGS IN THE North Cascades are a gift from nature. You can roam the backcountry for a week and return home with little to report beyond gray jays and ground squirrels, or maybe a mule deer and her fawn grazing a mountain meadow. There are countless other rewards, of course — the craggy summits, the solitude, the tranquility of the trail — but when it comes to actually seeing a storied carnivore, you’re better off visiting Yellowstone.

So I was as surprised as anyone when the stars aligned one July afternoon in 2014 while I was taking a lunch break with my two companions — my husband and field partner, Robert, and a friend — next to a sublime alpine lake near North Cascades National Park. We had been out there alone for days deploying wildlife cameras; there was still too much snow in the shadows for most summer-loving campers.

As I contemplated the snowfield across the lake, I uttered something aloud that I’d thought to myself a hundred times before: “I always hope I’m going to see a wolverine in a setting like this.” Just then, and I mean just then, I turned around to face a steep avalanche chute behind me. And there it was, not 200 yards away: a large animal loping low to the ground, its formidable form a masterpiece of wildness on a pure white canvas. The wolverine was gone within seconds, disappearing into the chute-side rocks and vegetation before our friend could zero in on its location. Fortunately, Robert saw it, too, or he would have thought I was dreaming. In the not-too-distant past, he probably would have been right.

Wolverines and their smaller cousins, Pacific fishers and Pacific martens, were decimated by Northwest trappers in the late 1800s and early 1900s — the latter two killed for their fur, the former mostly persecuted as trap-raiders. With habitat loss and widespread poisons for predator control dealing additional blows to already severely diminished populations, wolverines and fishers were eliminated from the Washington Cascades, and fishers were also extinguished from the Olympic Peninsula (where wolverines never occurred). Martens suffered a more complicated fate, having been left intact in the Cascades but perhaps on the brink of extinction in the Olympics.

Regional scientists are now using innovative technologies, diverse partnerships, and hiking boots on the ground to study these little-known mustelids (members of the weasel family) and try to assist them in their recovery. “Each suffered similar fates historically, but each has a very different status currently, resulting from divergent conservation stories,” says Keith Aubry, emeritus scientist at the US Forest Service’s (USFS) Pacific Northwest Research Station and global expert in mustelids.

Aubry is passionate about connecting the dots between the past and the present for rare mustelid populations so that we can better understand their needs moving forward. “You can’t know where you want to get to if you don’t know where you’ve been with these species.”

WOLVERINES WERE GENERALLY ABSENT from Washington for much of the twentieth century. There was a small rash of confirmed accounts in the 1960s — possibly wolverines who went on walkabout from Canada when their prey cycled high — but the species didn’t take root again until the mid-1990s. Then, Aubry and colleagues began to see a significant rise in verifiable records from the North Cascades, and in 1997, a female wolverine was struck and killed by a vehicle. The road-killed juvenile was wandering well west of the Cascade crest and outside of predicted wolverine habitat. Wolverines were definitely on the move, but where were they coming from, and were they finally here to stay?

Intrigued by the wolverine’s resurgence, Aubry and fellow USFS wildlife biologist Cathy Raley launched a collaborative wolverine telemetry study in 2005. “At that time, we didn’t know if there was a resident population — didn’t even know if there were more than occasional sightings,” Raley says. Over the next decade, Aubry and Raley worked closely with other agency biologists to trap and collar 14 wolverines in the North Cascades, allowing them to track these animals’ cross-country travels via satellite technology. One snapshot of data collected from a collared male named Special K shows he walked 11 straight-line miles through rugged Cascades terrain in a six-hour period; over a stretch of nine months, his wanderings covered a remarkable 1,000 square miles. I got to meet this tenacious solo climber once, while visiting a live-capture site in 2015. I’ll never forget his lion-like roar as he exited the log trap, or the massive, claw-clad paws that enable him to float across the frozen landscape and dig into its depths for a refrigerated meal.

Wolverines face a new suite of hazards from human activities, some of them presented by people who love wilderness.

Satellite data indicates that it might also have been Special K we’d seen at the lake in 2014 when we were out testing methods to monitor Washington’s wolverine population. Some researchers study wolverines by hanging a tantalizing piece of bait above a small wooden platform positioned opposite a motion-triggered camera. When the animal climbs onto the platform and looks up at the bait, it exposes its uniquely identifiable chest pattern to the camera. The problem is, two-legged access to Cascadian wolverine habitat in winter can be difficult, dangerous, or downright impossible at the scale necessary to replenish baits scattered throughout the wilderness. And during summer, wolverines apparently have better places to be than at survey stations — or better things to eat than a rotting beef bone. We needed a way to attract wolverines to our camera sites during the winter without having to get to them ourselves.

Imagine an IV-type bag that drips stinky liquid instead of medication. Now imagine this bag, a miniature pump, and its electronic controller stored in a bear-proof metal box secured to a tree 15 feet from the ground — high enough to remain above snow line even when it snows a lot.

In his role as a senior scientist with Seattle’s Woodland Park Zoo, Robert partnered with engineers at Microsoft and a state biologist from Idaho to create an automated scent dispenser for wolverines. The dispenser is programmed to release a tiny amount of lure (think: eau de skunk blended with anise) daily, eliminating the requirement to rebait camera sites in winter. This new technology has already been a game-changer for detecting wolverines in the North Cascades, increasing our detection rate more than tenfold during our pilot study in the winter of 2016-17. The dispenser was also used effectively in a multi-state wolverine survey conducted across Montana, Idaho, Wyoming, and Washington.

Robert long prepares an automated scent dispenser to attract wolverines during the winter months when the Cascades are hard for researchers to access. The dispenser will be hung high in a tree above the snow line. Photo by Paula MacKay.
Robert Long prepares an automated scent dispenser meant to attract wolverines. The dispenser, which will be hung high in a tree above the snow line, will assist researchers in their effort to study wolverines in the winter when the Cascades are difficult to access. Photo by Paula MacKay.

As Robert and his co-developers continue to tweak the scent dispenser’s design and Woodland Park Zoo strategizes to make this tool more widely available to researchers, wolverines are further expanding their range in Washington. Given genetic data and other available information, Aubry thinks these newcomers likely dispersed from the Coast Mountains of British Columbia. At least a few wolverines have even ventured south of Interstate 90 (I-90), the major east-west highway that bisects the Cascades near the center of the state. In early 2018, cameras deployed by biologist Jocelyn Akins photographed two kits near Mount Rainier National Park at the third reproductive den to be documented statewide (the first two were found in the North Cascades in 2012). Sadly, only a few months later, a 37-pound male wolverine met his demise trying to cross the same interstate, serving as a tragic reminder that people are still a threat to wolverines, even if over-trapping is a thing of the past.

Indeed, wolverines face a new suite of hazards from human activities, some of them presented by people who love wilderness. A recent study in the Rocky Mountains found that wolverines avoided areas of motorized activity (e.g., snowmobiles) and non-motorized winter recreation, such as skiing. Lead researcher Kim Heinemeyer and her co-authors speculate that “the potential for backcountry winter recreation to affect wolverines may increase under climate change if reduced snow pack concentrates winter recreationists and wolverines in the remaining areas of persistent snow cover.” I’ve heard Raley express similar concerns for the North Cascades, where a growing number of people want to live and play in the remote places wolverines need to survive.

Researchers have also predicted that climate change will reduce the spring snowpack that wolverine females in the Cascades and elsewhere rely upon for their reproductive dens. In 2010, this prediction and its dire implications compelled the US Fish and Wildlife Service to propose listing wolverines in the lower 48 states as threatened under the Endangered Species Act. The decision is still being batted about in the courts.

In the short-term, wolverines represent a best-case scenario for carnivore restoration, as they were able to return to Washington on their own and they’re finding what they need to thrive there. Fingers crossed, conservation efforts to promote habitat connectivity in the Cascades, including wildlife crossing structures on I-90, will enhance the wolverine’s chances of long-term recovery. Pacific fishers, on the other hand, needed a little more help.

“THIS NEVER GETS OLD.” It’s a damp December morning in 2018, and Jeff Lewis, a wildlife biologist with Washington Department of Fish and Wildlife (WDFW), is clearly elated as he welcomes the more than 100 people who have traveled to North Cascades National Park to witness the first-ever release of fishers into the surrounding forest. Lewis has worked on behalf of fishers for much of his career, having spent years studying them in California and Oregon prior to co-authoring Washington’s status report for this species in 1998. Today’s release marks the launch of the third and final phase of the fisher recovery effort he’s helped bring to fruition, with reintroductions having already been carried out in the Olympics and the southern Washington Cascades. Lewis sums up the project’s mission with heartfelt humility: “All you’ve got to do is bring them back, because the habitat is there.”

The solution sounds simple enough, but the task of ecological redemption is a long and windy road. WDFW’s recovery plan for fishers, also co-authored by Lewis, was published in 2006, eight years after the state listed the species as endangered. Like wolverines, fishers were thought to be gone from Washington. Unlike wolverines, however, the semi-arboreal fisher lives only in forests, and there wasn’t a source population close enough to naturally recolonize forested habitats in the Cascades or the Olympics. The fisher’s distribution in other Pacific states had been reduced to small, disjunct populations, and its range in southern British Columbia was contracted as well. The recovery plan’s conclusion? “A self-sustaining fisher population is not likely to become re-established in the state without human intervention.”

Between 2008 and 2010, 90 fishers were translocated to Olympic National Park, where they've hit the ground running. Photo by Kenic Bacher / NPS.
Between 2008 and 2010, 90 fishers were translocated to Olympic National Park, where they hit the ground running. Photo by Kevin Bacher / NPS.

To advance fisher recovery, Lewis and others created a core team of project partners consisting of WDFW, the National Park Service, and Conservation Northwest (CNW), a regional conservation group that had initiated and helped fund the feasibility assessment for a reintroduction. Dave Werntz, CNW’s Science and Conservation Director, felt the timing was right for the fisher’s return. “We had worked really hard for years to protect old-growth forest habitat, and we prevailed in that,” he says. “As we were looking toward now rewilding these habitats — bringing back species that were once here but had been extirpated for various reasons — we wanted to start with fishers, to get familiar with the process we needed to go through.”

Ironically, as part of this process, the fisher’s historical foe would become one of its saviors. With operational support provided by CNW, the project recruited Canadian trappers to help them source live fishers for translocation to Washington. Between 2008 and 2010, 90 fishers were moved from central British Columbia to Olympic National Park. The translocated animals hit the ground running, with at least three females giving birth in 2009. Fishers in search of new territory turned up in a variety of terrains, from mountainous forest to coastal plains. One motivated male, released in 2008, meandered all the way to the northwest tip of the Olympic Peninsula, traversing some 55 miles across a mix of federal, state, and private lands before arriving on the Makah Reservation at Washington’s Neah Bay.

The Makah Tribe agreed to help track the collared male with radio telemetry and later became engaged in more extensive fisher monitoring on tribal lands and neighboring forests. “We’ve always been supportive of fishers and the whole reintroduction,” says Shannon Murphie, Wildlife Division Manager for the tribe. “We were just curious to know what was really out there.” Partnering with Olympic National Park and the US Geological Survey, the Makah Tribe created the Makah Fisher Density Estimate Project in 2017. Tribal staff and volunteers set out 86 stations consisting of cameras and hair-snagging cubbies (for DNA), detecting seven individuals over a two-year period.

In the recovery process, the fisher’s historical foe would become one of its saviors.

“The tribes were integral partners,” says Patti Happe, Wildlife Branch Chief at Olympic National Park. Based on data collected by federal, tribal, and state field biologists, she’s cautiously optimistic about the population’s future, although she’s careful to say that fishers are not yet fully recovered. Happe is concerned about the fishers’ genetic diversity and wants to be sure that not just a few females are doing all the breeding — in which case, biologists would potentially need to bring in more animals to avoid inbreeding depression (a reduction in survival and fertility rates resulting from mating between close relatives). “We just need to get over this genetic hurdle, if there is one. Or, just give them time,” she says.

Meanwhile, the success of the fisher reintroduction on the Olympic Peninsula precipitated similar efforts in the Cascades. With a broad host of partners from the US and Canada, the core team released 73 fishers between 2015 and 2018 into central Washington’s Mount Rainier National Park and the Gifford Pinchot National Forest. Then, in late 2018, the project progressed to the North Cascades, where Lewis and his collaborators ushered their audience from the national park’s auditorium to the nearby release site. There, the team freed six fishers one by one from wooden crates, allowing them to re-enter a wild scene they’d been written out of almost a century before. Those animals have now been joined by 20 more. Ultimately, the researchers plan to reintroduce a total of 80 fishers into this portion of the recovery area.

Lewis says it’s too soon to say how the fishers will fare in the Cascades, although preliminary results are positive. “We’ll know a lot more once we complete our long-term monitoring effort in three to five years.” By then, he hopes the hand-picked pioneers and their offspring will have begun to fill a niche that has been vacant for far too long.

NORMALLY, BETSY HOWELL WOULD BE THRILLED to see a Pacific fisher captured on one of her motion-triggered cameras. A veteran USFS wildlife biologist in the Olympic National Forest, Howell knows these animals are very rare, and she is well-versed in the important role they have to play in forested ecosystems — by preying on small mammals, for example, and distributing berry seeds after consuming the fruit. But Howell’s disappointment is palpable as we scroll through our photos after a six-hour hike into the Mount Skokomish Wilderness. Coyote. Gray jay. Black-tailed deer. The camera’s memory card reveals the usual suspects. Then, “fisher!” I exclaim, as a brown, elongated animal — almost half bushy tail — pops up on our viewing screen. “Always good to see a healthy fisher,” Howell replies, her good-natured tone reflecting a glass half-full. Yes, fishers are an exciting find, but our quarry is the Pacific marten, much rarer on the Olympic Peninsula than the reintroduced fisher.

Martens once roamed the Olympic Peninsula. Today, researchers are trying to determine whether a viable population still exists there. Photo by David Moskowitz.
Martens once roamed the Olympic Peninsula. Today, researchers are trying to determine whether a viable population still exists there. Photo by David Moskowitz, Cascades Wolverine Project.

If wolverines look a bit like bear cubs and fishers can be compared to a hefty housecat, martens might be thought of as the fisher’s cute, feisty kitten. Weighing in at only 1 to 3 pounds, these compact carnivores are nonetheless capable of taking care of themselves in the forest. In his classic 1949 monograph, Mammals of the Olympic National Park and Vicinity, Victor B. Scheffer tells of a regional trapper who found feathers, rabbits, mice, squirrels, and spotted skunks in the stomachs of martens.

Historically, Scheffer writes, martens occurred throughout the coniferous forests of the Olympic Peninsula, “from salt water to timberline.” Recent genetic research conducted by Keith Aubry and colleagues suggests that martens in the Olympics originated from the Cascades thousands of years ago and then became isolated by geographical barriers. Although martens in the Cascades occupied mostly the high country, where they presumably enjoyed some protection from trappers, their ancestors in the Olympics inhabited a broader range of elevations. Those living down low disappeared with the fishers; Aubry thinks they were probably gone by the end of the Great Depression. “Once populations were impacted by over-trapping and habitat loss, it makes sense that they would retreat to their primary habitat in high-elevation forests where deep snowpacks form,” says Aubry.

Fast forward almost a century, and those high-elevation retreats may be all the martens have left. Since the late 1960s, there have been only 11 reliable marten detections on the Olympic Peninsula — all but the first two were above 2,000 feet — including a juvenile female found dead in 2008 on Mount Rose, in the southeastern corner of the peninsula. Aubry points out that this discovery was particularly important because it showed that martens were reproducing in the area a decade ago. Genetic analyses confirmed that the Mount Rose female was a remnant of the original population.

In 2017, Robert and I began a collaboration with Howell, Happe, and other agency biologists to help determine if a viable marten population still exists in the Olympics. As part of this research, we paired motion-triggered cameras with the scent dispenser initially designed for wolverines in hopes that we could detect rare and reclusive martens over the winter. Thus far, the project has photographed two martens in the upper Hoh River drainage, deep within Olympic National Park. This is the only place on the entire peninsula where previous camera surveys yielded detections as well, one in 2015, another in 2016.

Each photographic image is a glimmer of hope, but many questions remain about the status of martens in the Olympics. “I’m really concerned about how many are left and if there is enough genetic diversity for a healthy population,” says Happe, who acknowledges that a targeted augmentation (adding new individuals to a sparse population) may eventually be required to maintain martens on the peninsula. But for now, we will keep on trying to gather more information. As Aubry put it, we can’t know where we want to get to if we don’t know where we’ve been.

Nor can we achieve our conservation goals without opening our hearts and minds to the animals themselves. Martens, fishers, wolverines — in their own unique ways, these animals are telling us that to rewild broken landscapes with our scientific prowess, we must also internalize the life lessons we learn along the way. About teamwork. About resilience. About paying careful attention to the past.

You Make Our Work Possible

You Make Our Work Possible

We don’t have a paywall because, as a nonprofit publication, our mission is to inform, educate and inspire action to protect our living world. Which is why we rely on readers like you for support. If you believe in the work we do, please consider making a tax-deductible year-end donation to our Green Journalism Fund.

Get the Journal in your inbox.
Sign up for our weekly newsletter.

Subscribe Now

Get four issues of the magazine at the discounted rate of $20.