Parks and Panthera Study the East Bay’s Big Cats

Panthera teams up with the East Bay Regional Park District to study how an apex predator lives in remote wilderness and peri-urban areas like the Oakland hills.


Photo courtesy of the East Bay Regional Park District

By 8:30 a.m., the ridge in the Sunol Regional Wilderness is already in the high 50s, hot for a fall morning. Steve Bobzien grinds the pale green East Bay Regional Park District truck to a stop and gets out. A few minutes, later he’s kneeling besides a large oak tree with a camera trap the size of a lunchbox strapped a foot above the rocky ground. He runs a thick metal cable out of the camo-painted steel covering that holds it to the tree, and lets it land on the ground with a loud clunk. From inside he pulls out a camera lined with small LED lights. Bobzien, a wildlife ecologist, is in the 9,700-acre Sunol parkland this morning to find signs of one of the stealthiest apex predators left in the Bay Area: mountain lions.

With wolves and grizzly bears extirpated in California, few animals as iconic as the mountain lion remain in the state. Mountain lions were a bounty animal in California until the mid-1960s. Then, they were reclassified as a “game mammal” and could be hunted legally for sport. Today, mountain lions, also referred to as cougars or pumas, are considered a “specially protected mammal”—less severe than being endangered but protected from any kind of hunting. Because of their extremely shy nature and skill at avoiding humans, the size of the mountain lion population in the East Bay is unknown.

Bobzien is part of a new joint study between the East Bay Regional Park District and Panthera, a nonprofit focused on conservation of cats and their ecosystems worldwide. In what will be the first mountain lion study in the Bay Area in 20 years, they’ll try to understand the densities of mountain lions in the East Bay, from remote areas like Sunol to the peri-urban borders of Oakland.

At the rear of the truck, Bobzien starts assembling a makeshift field office. He sets up a metal table on four spindly, telescoping legs and hangs a blanket off the roof of the truck to block the glare of the sun on a wheezing laptop computer screen. The 59-year-old has wispy blond hair and wears a pair of binoculars that appear to never leave his neck.

At 19 he moved to the Galapagos Islands where he worked as a naturalist and research biologist studying sea turtles and fur seals. When he left for mainland Ecuador, he says he had to borrow a pair of shoes, because he didn’t own any of his own. Since then he has done research on seabirds and white sharks on the Farallon Islands off San Francisco Bay and spotted owls on California’s north coast. He has been an ecologist for the East Bay Regional Park District for more than 20 years.

Since Bobzien’s camera traps have been set up, they’ve captured images of a surprising variety of wildlife in these remote parklands. He photographed feral pigs, great horned owls, bobcats, and countless gray foxes. There are the inevitable black-tailed deer, turkeys, opossums, and coyotes, as well as golden eagles, badgers, and Cooper’s hawks. So far, he has identified nine individual mountain lions in the 11-square-mile area where his cameras are set up. It’s a surprisingly high density, but one that he attributes to the “bulls-eye” of strategically placing cameras where he thought the big cats would pass.

From the site of the camera traps where Bobzien is parked, the mountains of the Hamilton Range stretch south. To the north is Mount Diablo and, beyond that, the haze of the Oakland hills. The new study will focus on these three eco-regions. All three are mountain lion habitat, but each is separated into a sort of island by interstates 580 and 680 and the BART tracks. In addition to learning how many mountain lions live in these areas, the study will help researchers learn if they can cross from one to the next. After setting up more cameras, they’ll capture cats in the Mount Diablo Range and put GPS radio collars on them and do genetic sampling to learn if they’re isolated groups. But, Bobzien says, one of the biggest goals of all is getting people excited about what is basically the only apex predator left in Northern California.

“Kids latch onto that,” he says. “Frogs are kinda cool, falcons are a little cooler, but mountain lions are probably the coolest thing. That’s really important to maintain that interest in conservation, because if you don’t, you really can’t maintain these open space lands.”

Bobzien gets 736 images from the first camera, but most turn out to be cows let out by a local rancher, an annoying regularity. “I’ve had to go through 5,000 at a time, all cows,” he laughs. The second camera is only slightly better: “There’s a mouse. Squirrel. Here’s a ’possum. Mouse. Mouse again. Here’s the turkeys,” he says, scrolling through images. “Mountain lions do an amazing job of avoiding us.”

To prove it’s not all a wild goose chase, Bobzien opens a video, shot at this location the previous month. There, in ghostly green night vision, an adult female mountain lion and her kitten saunter through the frame, out for a night of hunting. “That’s like the holy grail for us,” Bobzien says, staring intently at the screen.

The camera traps didn’t catch their intended prey today. But Bobzien, undeterred, packs up his makeshift office, starts the truck, and heads down the ridge toward the next array of cameras, eager to see what he’ll find.

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