Tracking the Snow Cat

Hot on the trail of the lynx—the northern woods’ most secretive predator.

By Kim Todd

SIDEBARS: Political Animal | Where the Lynx Are

Photograph by Erwin & Peggy Bauer: Lynx (Captive)

It’s been raining off and on all morning, leaving the grass slick, the roads pitted with muddy pools, and the sky churning with sunshine and shadow. It’s spring in western Montana; the rivers are running high and the newspapers are running stories of capsized canoes and dogs washed away. Spots of snow still lurk on northern slopes while glacial lilies unfurl in patches of sunlight. And somewhere in the hills of the Seeley-Swan Valley, a Canada lynx curls in her den, watching over her two-week-old kittens.

John Squires, a research wildlife biologist with the U.S. Forest Service’s Rocky Mountain Research Station, is heading out with his crew to find her and other lynx that have recently given birth. They’ll spend the day locating dens, counting kittens, and gathering hair samples for DNA testing, and they’ve agreed to let me tag along. We are looking for F10, the first female trapped and radio-collared as part of Squires’s study. Usually lynx roam a mile or two a day, but when the females prepare to have kittens, they zero in on a small area as they choose a den, aiming to hole up for a while. Unlike F70, who will run for what seems like hours, dogged by a tired technician with an antenna in her wake, or wary F40, who eluded capture for years before they got a radio collar on her, F10 rarely gives the researchers any trouble. She chooses excellent dens and generally rears several kittens each year. She’s all you could ask for in a study lynx. The drizzle eases and rainsuits and boots start to dry, and everyone’s feeling lucky.

"It doesn’t matter, because we’re about to swim a river," laughs Jay Kolbe, the field crew leader. The west fork of the Clearwater surges past. Licks of whitewater grab at twigs and hunks of dirt, whisking them downstream. The signals from F10’s radio collar indicate she has chosen a site near last year’s den, just up the slope a bit on the other bank. We walk upstream, angling for a crossing, stopping at a spot where water pours over a lip, forming a green shelf edged with foam. The water would be up to my hips at least. This morning at the gas station market in Seeley Lake, I looked up at the stuffed lynx mounted above the cash register as it stared glassy-eyed over Fritos and cigarettes. At the time, I’d hoped it wasn’t the only lynx I’d see. Now, breathing in the chill river spray, I wonder if the taxidermal specimen might be enough.

Squires, taciturn, with a boyish freckled face etched with fine lines, squints at the river. He looks over at the four large technicians on his crew, looks over at me, and says, "It’s bad form to kill the writer." After trying and rejecting a third crossing, we pile back in the trucks and head toward a bridge that will lead us farther from the den, but to the right side of the stream.

We haven’t gone far, though, before the river widens out, shallow and clear enough to display the green and brown rocks at the bottom. "Look at that. You can cross right there," Kolbe says.

One of the field technicians walks over to Squires’s truck to consult. He reports back that Squires said there was too much energy in one of the corners. We drive on. What do I think he really said?

"Let’s not kill the writer."

Compared with the well-studied wolf and grizzly, the Canada lynx is a cipher. The northern cat is rare, notoriously elusive, and has a fondness for deep forests and remote landscapes. It has made a pact with winter, evolving to hunt on ridges at high elevations, chasing prey across snowbanks where other predators fear to tread. A lynx’s paws are about four inches across—as large as a mountain lion’s, though it’s no heavier than a bobcat. Dense fur around the edges turns its paws into feline snowshoes, allowing it to cross the fragile crust. Lynx eyes can discern slight shifts in light, the movement of a white hare on a white snowfield against a white sky.

Their lives are tightly knit with those of snowshoe hares, their primary prey. Lynx and hare populations in Canada cycle in tandem every ten years, though here in Montana, at the balmy southern end of their range, cycles are either nonexistent or much less pronounced. The cats can and do eat red squirrels, ground squirrels, and grouse, but an abundance of hares is lynx heaven. A lynx consumes up to 200 hares a year, and when the number of hares decreases to less than one per 2.5 acres, the cats often stop breeding. Early-20th-century naturalist Ernest Thompson Seton wrote that of all the northern creatures, none is more dependent on hares than the Canada lynx. "It lives on Rabbits, follows the Rabbits, thinks Rabbits, tastes like Rabbit, increases with them, and on their failure dies of starvation in the unrabbited woods."

Historically the cats occurred in 24 states, stretching south to Pennsylvania and Utah, but their range is retreating northward. Before reintroduction efforts, Colorado lynx were scarce; in Wyoming they are almost gone. In addition to Montana, 12 other states may still have lynx, although exactly how many is an unanswered question. The species is disappearing, and no one is sure why.

One of the reasons Lynx canadensis was placed on the endangered species list in 2000 was that data about the animal in the western United States were so scarce. In the Northern Rockies, the listing as "threatened" required amendments to plans for 4 Bureau of Land Management sites and 18 national forests. Some lynx-saving strategies have already been identified. For instance, we could stop culling trees from young forests before logging them—a practice called "precommercial thinning" that causes snowshoe hares to vanish. But overall, to manage for lynx, a much clearer picture of the reclusive cat is required. What does it eat in the summer? What makes one den more attractive than another? Which kinds of forests does it need? "If we had $50 million from Congress to recover lynx populations," Squires says, "we wouldn’t know how to spend it."

Efforts to bring the lynx back to its former range have been hampered by this lack of expertise. In the late 1980s, for example, 83 lynx were released in the Adirondacks, a place where the species started disappearing in the mid-1800s. Many were killed by cars, and recent surveys indicate that none remains. In Colorado’s San Juan National Forest in 1999 and 2000, many of the 96 lynx reintroduced starved to death, but at least 34 are still alive and biologists are planning to add up to 180 more.

Squires and his staff have been tracking lynx in western Montana for four years. They currently have radio collars on about 30 and spend days on end following them in Seeley-Swan Valley, a cleft through some of the most spectacular wilderness the United States has to offer. To the east, the Bob Marshall and Scapegoat Wildernesses stretch all the way to the rippling plains past the Continental Divide. To the west, the Mission Mountain Wilderness and the Mission Mountain Tribal Wilderness encompass sheer snow-covered cliffs. To the north, marmots whistle on the high peaks of Glacier National Park, smack against the Canadian border where a chain of protected areas reach deep into British Columbia. It’s no surprise that Canada lynx have chosen this steep-sided valley as one of their last strongholds in the Lower 48. Along with northwestern Maine and Okanogan National Forest in Washington State, the Seeley-Swan is one of only three documented breeding populations.

Before Squires’s research started, just three lynx dens had been described south of the Canadian border. Now he and his crew find that many in an afternoon. They track lynx movements from airplanes, study interactions with coyotes and mountain lions, and try to determine what kills them when they die. Between their work and that of scientists at the nearby University of Montana, the lynx is gradually coming into focus.

After walking alongan overgrown dirt road, a crew member raises a large antenna to locate F10’s radio collar. Swinging the antenna around, we wait for the strongest signal, telling us which direction to go. Taking readings from three different angles helps pinpoint the cat’s location. The steady blips say she’s resting in her den, occasionally moving her head, listening to researchers rustling in the brush.

Then, F10 is running.

The five of us thunder down the hillside, pushing through the tangle of rain-soaked subalpine fir, menziesia, and young larch, skidding over roots and rocks with antenna held high. Now that the researchers know the general area of the den, they fan out and check the most likely spots, peering under a fallen tree, shining a flashlight into a hollow log. Root boles, a rocky crevice—all need investigation. Lynx don’t dig their dens like coyotes; they find a natural niche and settle in. It could be anywhere in this thicket of tall trees and waist-high shrubs. Somewhere below us, the mother lynx doubles back. Carving sinuous curves into the shadows, she’s almost invisible, but not inaudible. The blipping of her radio collar says she’s staying close.

Though rarely seen, lynx often appear unconcerned by humans when they do encounter them. Early natural-history writers found this lack of ferocity disappointing. "[T]he lynx seems deficient in brains," wrote one observer in Forest and Stream in 1907, describing the animal’s tendency to wander into traps. "I consider them the meanest and most cowardly animal we have in Maine," said a writer named Manly Hardy, who complained that lynx hardly ever put up a good fight. These Montana researchers have noticed a similar nonchalance. Most of the time the lynx run, but Squires tells me how a crew member once walked by a female with kittens. As he paused to watch, the kittens continued to scamper, while the mother lay down and closed her eyes.

A piercing whistle cuts through the conversation. Someone has found the den.

At the base of a subalpine fir, backed by two rocks and shielded in the front by a screen of small yews, two kittens intertwine as if fighting in slow motion. Covered with gray fur, streaked with black on the face and the ears, each could fit easily in a cereal bowl. Their eyes, barely open, are startlingly blue. Their mouths gape as if to mew, but no sounds come out. One separates from the ball and stumbles away, its coordination so poor each step is a victory.

The den, a flattened patch of pine needles laced with long tawny hairs, seems too unprotected. There’s no overhang to shield the young cats from above. Frankly, the researchers are not impressed. They have come to expect better from F10. "This is an unusual den," Kolbe says politely. The mother paces below us, a blur between the trees.

One by one, Squires holds up the kittens, too young even to squirm with conviction, and checks the sex. A coworker plucks a few hairs and stores them in a vial. In the winter, when each kitten is big enough to wear a radio collar, they’ll capture them again. The tracings of their movement and the DNA testing on the fur will let the researchers build a family tree and delve into each lynx’s personal life. Who is its father? How far did it roam from its birthplace? How long will it live? If it’s a male, how far will he travel to mate? If it’s a female, will she take over her mother’s territory when her mother dies?

At L. Scott Mills’s Carnivore Conservation Genetics Labat the University of Montana, a lynx looks like this:two bright bands, hovering above a third, clustered near the bottom of a strip of Polaroid film. This distinctive pattern, based on the length of a certain section of the species’ DNA, differentiates it from a bobcat or a backyard calico. Though Mills is looking at the inner workings of cells, the portrait he gets of lynx is broader even than that gained by scrambling up hillsides and peering under fallen logs.

Mills has reddish hair and an energy that sends him bounding around the office to search for snowshoe hare statistics and an interesting article on DNA analysis techniques. He’s at the center of a suite of studies about lynx and hares. His DNA lab is an important component of the National Lynx Survey, a 13-state Forest Service effort to locate lynx. For the survey, technicians gather hair samples from scratch pads placed on trees and send them to Mills’s lab, where he determines whether or not the hair was left by a lynx (see "Political Animal," at left). In another study using different DNA techniques, he and colleague Michael Schwartz tested 599 blood, skin, and hair samples of lynx from the Yukon and the Kenai Peninsula down to Seeley Lake. They found that lynx 1,900 miles away from each other are genetically very similar. The lynx were much more closely related than far-ranging wolves or coyotes, both known for high levels of gene exchange.

These results suggest that lynx move long distances, dispersing from areas of dense population to seek untapped snowshoe hares or mates. Home ranges, especially in the United States, where habitat is patchy and snowshoe hares are not as plentiful as in Canada, can be up to 85 square miles. One male that Squires tracked traveled from the Wyoming Range to Yellowstone and back, a distance of 470 miles.

"We humans tend to think in a static way," says Mills. "If we just protect animals where they are, then everything will be fine. But in this case, movement really is important for sustaining lynx population dynamics."

Habitat fragmentation has already taken its toll. For example, lynx in parts of New England may have been doomed by mid-20th-century logging and development surrounding the St. Lawrence Seaway, which cut them off from the northern populations. There were numerous lynx sightings in Pennsylvania in the 1800s, but they dropped off sharply when forests in the northern part of the state were heavily logged at the end of the 19th century.

Even the Seeley-Swan Valley is shivering into smaller and smaller pieces. The Swan Mountains crouch to the east, their haunches a patchwork of logged and unlogged forests, reflecting their checkerboard ownership—alternating squares of government and commercial land. Timber companies are selling off tracts for subdivisions—and houses, lawns, and driveways may prove even less hospitable to wildlife than clearcuts.

In the winter, Seeley Lake echoes with the whine of snowmobiles, which carve up the landscape in a different way. Snowmobile tracks and even ski trails may compact the deep snow enough for coyotes to pursue prey into traditional lynx territory. The reintroduction of wolves to Yellowstone could be a boon to the cats, as the wolves clear out the coyotes and leave the snowdrifts to the specialists.

The next step for researchers is to determine what lynx perceive as a barrier between one forest and the next. "I would love to see where lynx are roaming every two seconds," says Schwartz. Improved technology nearly makes this possible. Squires is just starting to switch from radio collars to satellite collars, which can pinpoint the lynx’s location more frequently. Soon the far more precise global positioning system (GPS) collars will allow researchers to watch moment by moment as the animal swerves to avoid a road or clearcut, rejects one den and chooses another, or negotiates a good spot to cross the river.

As we gather the equipment and move away from the den, F10 shows herself again—first as a patch of fawn-colored fur glimpsed through the leaves, an ear, a foot; then she circles back, weaving through the underbrush, and stops in full view about 20 feet away. Her hind legs are so long they seem out of proportion, less like a cat’s than a sprinter’s in the starting block. The imbalance gives her a rangy look, slightly adolescent, gangly rather than sleek. Fur the color of dead leaves, of weathered branches, of the forest floor explains how she can hide at close range. Tufts on the top of her ears flick our direction, long paintbrushes dipped in black. She looks back at us with pale yellow eyes. Being held in the gaze of a wild carnivore causes a heightening of the senses, a tightening of muscles at the back of the neck. It’s nothing like I imagined. All of the statistics, den measurements, DNA samples, radio-collar data, all carefully gathered, cannot capture this gold stare. I hold my breath. She cuts away.

Kim Todd is an environmental writer and author of Tinkering With Eden, a Natural History of Exotics in America.