Predator protector: Winston Vickers’ research aims to give California mountain lions a fighting chance

Winston Vickers’ team has installed dozens of strategically placed cameras in the Orange County backcountry to track where mountain lions roam, making his screen feed one of the most suspenseful in the state. Vickers is currently waiting for a mountain lion to approach a deer carcass laid out in the Santa Ana Mountains by one of his team’s biologists. They hope to entice a cougar with a free meal so Vickers can collar it and track it with a GPS tracker.

Vickers, 68, is the director of the California Mountain Lion Project at UC Davis’ Wildlife Health Center and one of the country’s most knowledgeable cougar experts. He extols the virtues of his close encounters with the majestic predators.

“Oh my gosh, look at their claws and those teeth when you handle them!” “They weigh about the same as me,” the tall and trim gray-haired researcher says, his voice tinged with playful envy, “but holy smokes, they’re all muscle!”

The UC Davis project, which has been working with mountain lions in Southern California for over two decades, employs cameras and tracking collars to investigate habitat, health, and human interaction issues as the line between wilderness and development becomes increasingly blurred.

The Santa Cruz Puma Project, founded in 2008 by wildlife biologist Chris Wilmers, is a similar organization in Northern California. The collaboration between UC Santa Cruz and the California Department of Fish and Wildlife focuses on Bay Area mountain lions, using collars and cameras to track them, as well as projects like the wildlife underpass at the Laurel Curve, which opened in January and provides safe passage beneath Highway 17.

The underpass, built in collaboration with the Land Trust of Santa Cruz, benefits more than just mountain lions, according to Wilmers. There was evidence of squirrels, deer, wood rats, and gray foxes using the underpass within hours of its cameras going live. Researchers are only now beginning to collect specific data on how well it works.

Vickers and Wilmers’ research has a common impetus: the survival of California mountain lions in both the Santa Monica and Santa Cruz mountains is threatened by inbreeding, human interference, and car accidents.

“Cars and roads, in a nutshell, are the main cause of their deaths,” says Vickers of Southern California.

According to Wilmers, traffic accidents are second only to humans seeking vengeance against mountain lions that kill livestock and pets in the Bay Area.

Mountain lions can be harmed by rodenticides, but it is rarely the primary cause of death, he adds. Mountain lions are top predators that prey on larger animals. However, rodenticides can weaken mountain lions’ immune systems, making them more susceptible to illness and death.

“Every (dead) mountain lion we find has some amount of rodenticide in its system,” Wilmers said. “It is very widespread.”

The vast networks of highways and interstates created by urban development pose an additional threat to animals that most people do not consider. Mountain lions are unable to move freely due to the barriers. As a result, populations suffer from inbreeding. Vickers has witnessed mountain lions approaching a freeway, sitting for hours as cars and trucks speed by, and then turning around because they are afraid to cross.

If not addressed, the lack of genetic diversity in an inbred population could doom the state’s estimated 5,000 mountain lions. Scientists have already observed newborns with deformities such as kinked tails. Vickers played an important role in a recent study that discovered that 93 percent of male mountain lions have abnormal sperm.

“There’s a race to the bottom,” he observes.

He and other experts believe that if the state does not take drastic measures to help mountain lions survive, they will be locally extinct by 2050.

Vickers, the son of a country vet, grew up on a cattle farm in the Ozarks. “We treated every creature, small and large, from cats to cows,” he said.

He describes himself as a kid who was “always fishing, hunting, and canoeing.” He vowed not to follow in his father’s footsteps, but after a few semesters of engineering, the call of the wild was too strong, and he decided to pursue veterinary medicine instead.

“What my dad really gave me was appreciation for animals and caring about their welfare,” he said.

When Vickers began working as a veterinarian, he became a vegetarian “because I couldn’t really see the value of working so hard to save the life of one cow only to then kill it for a steak.”

For nearly two decades, he worked as a regular vet in Arkansas and California, while also accepting any opportunity to treat wildlife. His interest in big cats took him all the way to Nepal to study snow leopards. In 2002, he joined the Mountain Lion Project at UC Davis after earning a second degree in epidemiology. The vets there had started out researching endangered bighorn sheep in Anza Borrego State Park and saw mountain lions as a threat to them.

“We were soon shocked to find that the mountain lions had an unusually high mortality rate,” Vickers said. As a result, the researchers began tracking mountain lions, amassing 20 years of detailed knowledge about the elusive animals. Data on the big cats’ critical habitats and corridors has become critical for conservation efforts.


Vickers is one of those who advocate for wildlife crossings over major highways so that local mountain lions can mix and mate with peers from neighboring habitats. Caltrans recently broke ground in the Santa Monica Mountains on the world’s largest wildlife overpass, dubbed the Liberty Crossing over busy 101. The new bridge, which is scheduled to open in 2025, will cost $88 million, which seems exorbitant until one considers the alternative: Wildlife crashes in California have cost more than $1 billion in the last three years.


The crossings benefit wildlife of all kinds. Wildlife crossings have reduced fatal deer collisions by 98.5 percent in Utah and nearly 90 percent in Colorado. A recent study discovered that apex predators such as pumas act as “ecological brokers” and play a “outsized role” in the health and biodiversity of their territories.

Highway 101 near the border of Santa Clara and San Benito counties will get another overpass. In December, the nonprofit Land Trust of San Cruz County paid $17 million for a 2,600-acre parcel of land near San Juan Bautista. The trust is now collaborating with Caltrans to construct a 120- to 160-foot wide wildlife crossing that will allow mountain lions, deer, bobcats, badgers, foxes, and other animals to safely cross the highway.

Vickers hopes to persuade the state and environmentalists to add several smaller crossings in Orange County as well as improve the existing freeway underpass near Temecula Creek. He will soon begin meeting with experts and engineers from Caltrans, the Nature Conservancy, the National Park Service, and other organizations to determine the best crossing designs and locations “to help as many species as possible.” Mountain lions have become the poster animals for the barriers, but they also affect many other animals, including birds that don’t like to fly over freeways.”

It is important to provide safer routes for animals to navigate their territories, but it is not the only thing that can be done to ensure mountain lion survival.

“No. 1 is to stop the sprawl of development,” Wilmers says. “Construct in existing cities.” Second, many mountain lions are killed when they kill someone’s goats. People frequently keep their goats in pens at night, which helps them keep track of them but provides no protection against predators. They should keep their goats in a fully enclosed structure with a roof if possible.”

Recognizing that “it’s hard to get people to change their behavior and spend money to build a barn or a secure cage for their animals at night,” Vickers focuses on youth. “Educating the young when they’re at the formative stage on how to protect animals, hopefully, that’s a long-term solution.”

When asked what he admires most about the charismatic cougars, he extols their tenacity.

“Despite dramatic persecution, they have been the most successful of the big carnivores to persist,” he says, his raspy voice filled with awe. “You just have to admire their ability to continue to exist against all odds.”

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