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Skye looks official in her orange vest. She takes in her surroundings, gathering details that would escape most observers. With bright eyes and ramrod posture, she’s ready to work. But first she has to pee. She squats on her haunches, then trots off down a sandy track.
Suzie Marlow jogs after her. Marlow and Skye both work for Rogue Detection Teams, a company based in Washington State that enlists dogs to track wildlife for conservation research. Today, the pair will search for Humboldt martens.
Martens belong to the weasel family and look a bit like squirrels that have been stretched out and trained for battle: cute, but ferocious. They have long bodies and short, toothy snouts, with oversized ears that protrude above piercing black eyes. Their lush brown fur brightens to gold on their chests, and their powerful limbs end in bouquets of razor-thin claws.
Most Pacific martens live in the mountains, but Humboldt martens—a rare subspecies—make their home along the coast. They once ranged from Northern California to the Oregon-Washington border, filling the ancient, towering forests that fringed the Pacific shore. Now, they’ve all but disappeared, and recently gained formal protection under the US Endangered Species Act.
To everyone’s surprise, however, scientists discovered one of the few remaining populations here, on a strip of overgrown sand dunes 75 kilometers long and half a kilometer wide. This stand of moss-cloaked shore pine and punishing shrubs in the Oregon Dunes National Recreation Area—where I now trail Skye, Marlow, and Marlow’s colleague Jennifer Hartman at a COVID-safe distance—looks nothing like the majestic old-growth forests of yore. But the martens don’t seem to mind. Indeed, this is the densest population anywhere on Earth.
It’s also one of the most imperiled. The martens face threats from cars, development, and worst of all, isolation. More than 100 kilometers of fragmented forests and roads separates them from their nearest neighbors and the genetic diversity they could bring to a population living under involuntary quarantine.
Researchers hope that by understanding how these animals have hung on despite such pressures, they will glean clues about what Humboldt martens in general need to survive and, perhaps, someday thrive.
After a few minutes of walking, Skye bolts into the brush. Marlow follows, forcing her way through a wall of vegetation with no obvious human-sized openings. As we bushwhack after them, Hartman jokes that this is what you might call “crapitat.” I had already seen the evidence: Hartman’s purple backpack, which looks as if it has been mauled by a bear. “This,” she’d said, “is what Humboldt marten hiking does.”
For decades, scientists feared that Humboldt martens had gone extinct. Then, in 1996, researchers spotted telltale prints on a track plate left in the woods of Northern California. In the years following, they found more signs of the animals.
Perhaps the marten’s resurrection shouldn’t come as a shock. The animals have scrappy, bold personalities. “Think, like, a 17- or 18-year-old teenager,” says Katie Moriarty, a wildlife ecologist at the National Council for Air and Stream Improvement, a research institute established by the forest products industry. “They will do whatever they want.”
Humboldt martens are fiercely territorial. They constantly patrol the borders of their home range, traveling an average of six kilometers a day. “You have an animal that’s the size of a kitten,” Moriarty says. Yet “they are moving almost as much or more than a mountain lion on a daily basis.”
To maintain such an active lifestyle, a marten must eat up to a quarter of its body weight every day, in the form of chipmunks and songbirds, berries and insects. Martens enjoy other foods, too, including bacon and strawberry jam, which Moriarty uses to bait and feed her research subjects when she captures them. “You want to basically give them a bed and breakfast in the trap,” she says.
Martens themselves make tasty snacks for predators like bobcats and owls, so they stick to forests with plenty of shrubs and downed trees where they can hide. They raise their young in the protected cavities of trees and snags. But these strategies haven’t shielded them from the greatest threat of all: humans.
By the time the naturalist Joseph Grinnell identified Humboldt martens as a distinct subspecies in 1926, demand for their luxurious pelts had already made the animals scarce. California banned trapping of coastal martens in 1946, but then came industrial logging. Timber companies harvested the biggest, oldest trees in which martens made their dens. And clearcuts left little protective cover on the landscape. Today, Humboldt martens occupy just seven percent of their historical range.
Scientists now know of only four populations, each estimated to contain fewer than 100 adults. One resides just east of Redwood National and State Parks in Northern California. One straddles the California-Oregon border, and another hugs the southern Oregon coast near the Rogue River. In these three, most marten sightings have occurred in large patches of old-growth forest.
But the population on the Oregon dunes, which Moriarty and her colleagues first documented in 2015, is by far the most intriguing. “That’s kind of changed everyone’s thinking about Humboldt martens,” Moriarty says.
Skye hits on her first marten scat in a grassy clearing. She waits eagerly for her reward, her large black ears quivering above her brindled brow.
Hartman logs the find, noting its location and appearance. Then she picks up the scat using two reeds of dry grass as chopsticks to avoid contaminating it with her DNA. She catches a whiff of its sweet, musty aroma—a hallmark of the weasel family—then stuffs it into a Manila envelope to dehydrate later. Given the animals’ tenuous situation, scientists try to limit handling live martens as much as possible and to exploit noninvasive techniques like studying their poop. Later, Moriarty and her coworkers will analyze the genetics of the scat to help determine how many martens live here and what they’re eating.
Meanwhile, Marlow pulls a yellow ball from a leg harness she wears for quick access and tosses it to Skye. For the next several minutes, they play a game of fetch that is more theoretical than literal: Marlow lunges at Skye as if to take the toy and the delighted dog chuffs, rolls, and bows over her prize.
Skye is a stout, midsized mutt. And like the other Rogue dogs, she’s a rescue—a misfit of sorts. She came from a shelter in New Mexico, where it became clear that she wasn’t cut out for the leisurely life of a family pet. But she’s well-suited to her new vocation, which has involved searching for endangered pangolins in Nepal and surveying wind farms for bird and bat casualties. “We’re actually trying to change the conception of what a bad dog is,” says Hartman. Far from problem cases, the Rogue dogs “are wildlife heroes.”
Like Skye and her ilk, the dune martens haven’t always fit in. Their existence challenged the long-held belief that martens primarily live in old-growth forests of redwood or Douglas fir. The short, gnarled trees here are no bigger than a fir branch, and the forest itself is young and somewhat artificial. Rolling dunes used to cover the area, but in the early 1900s, government agencies and private landowners planted beach grass to stop sand from blowing onto coastal roads. The grass stabilized the ground enough for shrubs to root, including invasive Scotch broom. Trees eventually followed, and by the middle of the century, a scrubby forest had sprouted.
Moriarty’s discovery of martens in these woods stunned everyone. The animals had occasionally turned up flattened on Highway 101, which separates the dunes from the rugged mountains to the east, but most scientists assumed the animals died while venturing toward the ocean. In reality, it was the other way around.
Research by Moriarty and her team has revealed that the shore pine forest makes a good home for martens because of its dense understory and abundant food. In fact, the 70-odd martens here have the smallest home range of any in the world. “They’re as packed in as they can get,” Moriarty says.
She’s come to suspect that the martens’ presence in this strange environment is actually a window into their past. Similar stands may have grown along flat, sandy stretches of the Oregon coast before towns and housing developments replaced them. And martens likely used that habitat until it vanished.
The real question, then, isn’t why the martens are here. It’s why there are so few of them in the vast inland forests that once formed the stronghold of their range.
Before scientists started looking for Humboldt martens in Oregon, they figured they would find plenty in the sea of conifers that washes over the western edge of the state like a green tide. “We didn’t really have any reason to believe that martens weren’t there,” says Sue Livingston, a biologist with the US Fish and Wildlife Service (USFWS).
That rationale factored into the agency’s decision not to protect the animals in 2015, prompting environmental groups to sue. But as researchers ramped up survey efforts in the state over the next few years, they didn’t find many martens at all. In fact, Moriarty hasn’t detected a single one in the Douglas fir forests across Highway 101 from the dunes.
No one knows exactly what’s holding them back in Oregon—and in California, for that matter. It appears as though pockets of suitable habitat still exist, Livingston says, but they are separated and surrounded by previously logged forests where martens encounter threats like predation. Bobcats, in particular, may thrive in young, fragmented forests. In one study, they killed roughly half of the radio-collared martens that scientists were tracking in a heavily logged forest in Northern California. On the dunes, by contrast, researchers rarely spot bobcats.
A lack of shrubs probably also hurts martens in plantation and second-growth forests, since understory plants struggle to grow beneath the closely spaced trees, says Taal Levi, a wildlife ecologist at Oregon State University. Alternatively, martens may have just taken too big of a hit to bounce back, Livingston says. Roaring rivers, busy roads, and sprawling clearcuts stand between existing populations and other possible habitat, presenting formidable barriers to natural dispersal.
The last remaining martens have it hard enough. Without newcomers, the chances of inbreeding go up among these isolated groups, bringing heightened susceptibility to disease and other stresses. Martens also face threats from rodenticides and wildfires, which have recently consumed substantial chunks of their habitat in both Oregon and California.
Sorting out the importance of these factors could have significant practical implications for marten conservation. “They are extremely imperiled,” Levi says. But right now, “it’s not at all clear what one should do.” Levi did take one obvious step: he helped pressure Oregon officials to ban trapping on the dunes and in most of western Oregon in 2019.
Some private timber companies, which own much of the land in coastal Oregon and Northern California, have changed their operations to benefit the animals. Under an agreement with the California Department of Fish and Wildlife, the Green Diamond Resource Company has been sparing trees with large cavities and active dens. And they’re leaving logging debris on the ground to provide cover, says Keith Hamm, conservation planning manager for the company’s California timberlands. “I’m not saying that everything’s well and good,” he says. Still, “the more we look, the more [martens] we find.”
But these efforts don’t go far enough, says Tierra Curry, a scientist at the Center for Biological Diversity, a national environmental organization that has sued repeatedly to secure federal protection for Humboldt martens. She’d like to see landowners set aside corridors of forest to reconnect populations and restore potential habitat.
The Siuslaw National Forest is already trying to promote old-growth conditions in the Douglas fir forests north of the dunes. But it will take decades before those efforts have any hope of benefiting martens, which need help now, Levi says. He would rather see managers try quicker, more targeted measures like thinning trees in replanted stands to encourage shrub growth.
Some researchers have floated the idea of relocating animals to help them expand their range, but Levi and others fear it may be too risky.
Humboldt martens will likely receive more attention now that they have won protection under the Endangered Species Act. The August decision, which came two years and a lawsuit after the USFWS first recommended listing the animal as threatened in 2018, could bring more funding for marten research and conservation.
But listing can also bring challenges, especially if efforts to save a species pit certain industry or advocacy groups against each other. To restore marten populations across their historical range, everyone will need to work together, Moriarty says. “As soon as it becomes an us-versus-them issue, I don’t feel like the martens win.”
From somewhere in the woods, Marlow lets out a whoop. “Oh, good dog! That was so good! Good job!” she says in a singsong voice. Skye has found another marten poop. “It smelled really good,” Marlow tells Hartman as they collect the scat. It looks like a pair of dun-colored cheese puffs.
The paradox of the dune martens is that, despite their high density, the population also teeters on the verge of annihilation. The dunes actually host two groups of martens, separated by the Umpqua River, and each has barely enough adults to remain viable. For both, losing just two to three adults per year could send the population spiraling toward extinction, according to a 2018 study by Moriarty and her colleagues.
And new threats continue to arise. A Canadian pipeline company hopes to build a liquified natural gas terminal on private land at the southern end of the dunes. The Jordan Cove Project recently gained a key federal approval, though the state has so far refused to grant several permits, leaving its fate in limbo.
The US Forest Service also plans to rip out invasive plants growing on the dunes to restore the area to its natural state and benefit species like snowy plovers—threatened shorebirds that nest in open sand. But Moriarty and others have warned that doing so could disturb the very vegetation upon which the martens rely. Now, the agency must aim to strike a delicate balance as it proceeds with restoration efforts in the coming years.
The many pressures martens face only underscore the urgency of scientists’ work here. Walking back to the car at the end of the day, Hartman and Marlow confess that searching for Humboldt martens demands more—both physically and mentally—than the other animals they study. “If we could pick, no one wants to do this one,” Hartman says. “But I think it actually might be one of our more valuable projects.”
Marlow agrees. “I’m not out there collecting poop for fun. I’m working my butt off for a reason.”
So is Skye. Trotting ahead—nose low, ears high—she is a dog on a mission. Perhaps this misfit can help another find its place in the world.