He invites us to use all our senses to assess the living landscape, listen for avian alarm calls, watch for signs of prey activity, and note where vegetation might provide cover for prey or predator.

Bobcats, like mountain lions, are opportunistic ambush predators. They take cover, waiting patiently for their favorite food to appear—deer, in the case of lions, rabbits and rodents for bobcats (though they’ll settle for raccoons, turkeys, really anything within reason).

Scanning the steep hillside just east of the trail where our group stops for instructions, I notice triangular tufts of grass emerging from the hillside. Could be rodent residences. Just to the left of the tufts, a long run stretches from the base of the hill to its crest. If I were a bobcat, that’s where I’d settle in.

bobcat tracks — The two front paws of a bobcat. Bobcats, like lions, tend to move slowly and stealthily, often pausing to look for prey, taking care not to betray their presence. (Photo: Courtesy Mark Elbroch)

“We’ve seen lots and lots of signs of bobcats,” Davidson says. “They didn’t disappear. They’re resting in bushes somewhere with good cover. Listen to the birds. They might have something to say about that.”

If the birds are telling me something, I don’t know what it is. I start scaling the steep hillside, slipping on the parched golden grasses to reach the tufted rises. Sure enough, the tufts cover little dugouts, carved out of the dirt. Could be burrows for voles, pocket gophers or ground squirrels. I head toward the run skirting Rodent Central, looking for footprints and scat, but see nothing.

Nearing the crest of the hill, I spot a well-worn run ringing a dense stand of firs and large boulders, which cats big and small use for cover. At the top of the hill, I see a rather large scat on top of a rock.

Unfortunately, though scat is easy to spot, it’s notoriously difficult to tell who left it.

Evidence-Based Tracking
Ecologist and master tracker Mark Elbroch says "there's nothing esoteric" about what he does. "It's really just looking for signs that betray the passage of an animal. And knowing where to look."

He's looked at scat “for years and years and years,” and still comes across specimens he just can’t identify.

In a 2011 population survey of snow leopards in Nepal, genetic analysis showed that 52 of 71 scats identified as snow leopard in the field came from another carnivore (probably fox, dog, wolf, or lynx), even though the highly trained field team followed an exacting protocol.

Nearly every project that relies on scat to study the diet of felids ends up mixing felid and canid scat, says Elbroch, who’s studied lions in California, Colorado, Patagonia, and now, as leader of the Teton Cougar Project, in Wyoming.

Yet some general rules apply, he says. Bobcats and coyotes both mark trails, so you’ll likely encounter them on a hiking trail, deer run, or along a ridge path. But mountain lions almost always hide their scat.

After killing a deer, mountain lions drag it into cover, if they can, and usually cache it or cover it with debris, Elbroch explains. And they’ll form a latrine close by, from 15 feet to a quarter mile away, where they’ll defecate time and again over the course of feeding on the carcass.

Lion scrape in Patagonia — Lions leave deep impressions in dirt made with their hind feet to mark their territory or signal their presence to females and other males. Multiple lions may use the scrape site like a community bulletin board. Juan Carlos Bravo sits next to a scrape in Patagonia. (Photo: Courtesy Mark Elbroch)

When Elbroch looks for lions, he relies more on footprints and scrapes, depressions made with the hind feet, than on scat.

Mountain lions use scrapes as community bulletin boards, Elbroch says, a behavior documented on video cameras. “You’ll see females coming in to check the males. They smell the site and start yowling, going into heat.”

“Chris Wilmers has great footage of a male coming in and scraping, another male coming in, smelling the scrape, then walking through, then a female coming in and smelling the scrape.”

Since all the lions are collared, Wilmers, a UC Santa Cruz biologist who leads the Bay Area Puma Project, could tell that the female and male in the footage spent three days together—typical for a romantic interlude.

Sharing the Spoils
Thanks to video cameras and advances in GPS technology, the hidden life of mountain lions is slowly emerging. In a recent study from his work in Patagonia, at the southern tip of South America, Elbroch used GPS collars to show that lions help feed their neighbors. Often, the big cats lose their hard-earned meals to other hungry animals. In California, a black bear may scare a cat off a carcass. In Patagonia, Elbroch found, lions supplied more than 500 pounds of meat per 38 square miles to a diverse community of scavengers, including the increasingly rare Andean condor.

“A cougar kills something in the open then retreats to cover, because it doesn’t want to sit in the middle of a big grassland all day,” he explains. “But it doesn’t go back, because it knows it’s already gone.” The Andean condor, cousin to the California condor, makes fast work of the remains.

That means lions have to kill more prey to avoid starvation. It also means lions function as a wilderness grocer.

Elbroch's videos show everything from weasels and martins to foxes, coyotes, and wolves to grizzlies and black bears feeding on a kill. “And the insect life on top of carcasses is crazy. That draws in the birds.”

In Wyoming, he adds, “we got this amazing footage of a flycatcher sitting above the kill and just zipping down in little dives right over the carcass, just cleaning up on all the flies.”

Humans Aren’t on the Menu
Specialist hunters, lions focus on large ungulates like deer and elk, which provide enough meat to offset the energy spent hunting, even with all the food lost to scavengers. Lions, as every expert will tell you, prefer to avoid humans. So how to explain the recent attack on a 63-year-old Marin County man camping near Nevada City?

“Well it’s total speculation,” Elbroch says. “It happens so rarely, the sample size is so low, it’s hard even to guess.”

Still, the first thing Elbroch wondered was whether the lion was attracted by a wheezing snore, which can sound like a dying animal. “Cats don’t just walk up to people and bite them. But if they were to walk by and hear rustling movement and this weird snoring wheeze, you bet they’re going to come up and check it out. They are incredibly curious.”

In fact, Elbroch uses tapes of whining foxes or rabbits—whines being universal signs of distress—to attract lions to pit snares, so he can outfit them with a GPS collar or check on them during a study. “It's the easiest way to pull in a lion.”

After two lion attacks in Cuyamaca Rancho State Park near San Diego in the 1990s, researchers got funding to study the behavior of 10 collared lions who used the park. Even as the number of people using the park increased, with close to 600,000 visitors in 2002, cats and humans rarely had occasion to meet.

Cougar track — Tracks of an adult female lion, taken in Los Padres National Forest, California, next to Mark Elbroch's footprint. (Photo: Courtesy Mark Elbroch)

"They're sleeping right next to the trail, and using the trail all the time, but generally at night,” Elbroch says. “The lights go out, the lions start using the trail. The lights come on in the morning, the lions just walk 50 to 100 feet off the trail and lie down for the day. Horses and people go by them all day, every day. And there’s never an encounter.”

Lions, like wolves, play beneficial, essential roles in maintaining healthy ecosystems, Elbroch says. “We shouldn’t just consider them vermin or competition or threats to our children and livestock, which is how we looked at wolves forever. Now people are starting to talk about the ecological benefits of wolves. It would be great to get there for mountain lions, too.”

To help Bay Area residents appreciate these benefits, the Felidae Conservation Fund has outfitted the hills we’re exploring with motion-sensitive cameras. The “camera traps” don’t just produce compelling images of wildlife, they collect data, preparing for the day when the Bay Area Puma Project reaches Marin. (The next Catscapes outing is Saturday, July 21.)

Before heading back down the hill to rejoin the group, I take a quick detour to see what lies beyond a nearby ridge. When cats hunt, they often travel just below the ridgeline, out of sight, but close enough to pop up and peer over into the next drainage, looking for deer.

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Tracking Big Cats to Learn Their Secrets