Scientists are chasing mountain lions through California’s backcountry in the most ambitious research project ever focused on the state’s famed predator — and it could change how the species is managed.
The statewide California Department of Fish and Wildlife project will establish an estimated population count of mountain lions for the first time in decades. Researchers are working in the field and lab — analyzing mountain lion genetics to identify family groups, tracking how mountain lions use habitat, and developing tools to monitor population trends into the future.
“It is the biggest (research project) we’ve ever done before analyzing this particularly elusive species,” said Vicky Monroe, the department’s statewide conflict programs coordinator.
Most of the Golden State is mountain lion habitat — from the hills above Los Angeles to the grasslands of the Modoc Plateau in the northeast corner of California — and sightings seem to be increasing. Yet little is known about the health and population of the wild cats in each region of what is a large and ecologically diverse state.
There’s also no overarching state plan to manage the apex predator that’s called a key to biodiversity by conservationists and a threat to livestock by ranchers.
The lack of data is a problem for the agency that’s tasked with protecting the state’s natural resources.
“Regardless of what you hear, we don’t know how many there are,” said Justin Dellinger, a senior environmental scientist with Fish and Wildlife’s Wildlife Investigations Laboratory. He is leading the statewide research.
“If you don’t know how much of something there is, you don’t know their status. You don’t know what you need to do to protect them,” he said.
So far, field research for the project has sent him hiking across the rugged terrain of the eastern Sierra Nevada and crawling through the dense chaparral forest of the coastal Santa Lucia Range in search of the skittish wild cats.
Fish and Wildlife is building on the work of regional mountain lion research that has already been done, and partnering with Wildlife Services, State Parks, universities and nonprofits to employ traditional and new methods of field research to produce statewide and region-specific population estimates by 2022.
The idea is to ultimately create a conservation and management plan that identifies threats to mountain lions in each region and suggests potential policy changes, followed up by regular monitoring of the population.
The state of the California cougar
For decades the state has cited a statewide population estimate of 4,000 to 6,000 cougars, but Fish and Wildlife officials admit that’s a guesstimate based on what researchers believed to be an average population density across potential habitat.
Cougars have survived a complicated history in the West, despite efforts by European settlers to eradicate predators.
“We did a good job of eradicating every large mammal we set our sights on in the West: bears, wolves. We weren’t able to do it with lions. They’re elusive,” Dellinger said.
“Plenty of (lions) have shown they have an ability to live in and amongst us without being detected. Until recently, with security cameras and game cameras, the public never had any idea how much they were in and around mountain lions on a regular basis.”
A bounty on mountain lions from 1907 to 1963 resulted in thousands killed, yet even as pay-per-carcass increased from $20 in 1907 to $50 for males and $60 for females in 1945, some of the stealthy night-stalkers survived.
“It’s likely populations have increased since then,” Dellinger said. “But we don’t know if they peaked in the ‘80s and stabilized since then, or peaked more recently. It’s impossible to say.”
Humans continue to be cougars’ biggest threat.
Voters out-right banned hunting in 1990, after a yearslong moratorium. But the wild cats can be killed with “depredation permits” that are issued by request when a domestic animal has been killed by a lion. An average of 98 mountain lions are killed each year through those permits, and there’s no good data on how each loss affects most regions.
Cougars pay the ultimate fine crossing California roads. Fish and Wildlife does not have a system to track and record lion-vehicle strikes, but a public-sourced online roadkill tracking system run by U.C. Davis documented more than a dozen mountain lion kills since the beginning of 2017 and many go unreported.
The population estimate hasn’t been updated, in part, because lions are hard to track and expensive fieldwork has remained unfunded. Conservation research, in general, is funded with hunting fees, and hunting lions hasn’t been allowed in California since 1972.
Fish and Wildlife is able to fund a bulk of the new statewide mountain lion project with federal money from an excise tax on sporting arms and ammunition, after officials were able to draw a connection between lions and their affect on hunted species, like deer and big horned sheep.
A regional approach
Already, researchers with the Fish and Wildlife population project have made a discovery. Scientists tested the DNA of more than 1,000 dead mountain lions in the state, which spans 163,000 square miles, and found evidence of 10 distinct sub-populations — as if groups of lions in each region share a great-great-grandfather.
Each of these 10 regions is considered a home to a unique sub-population: Eastern Sierra, Modoc Plateau, Western Sierra, North Coast, Santa Cruz Mountains, Central Coast, Santa Monica Mountains, Santa Ana Mountains, San Gabriel/San Bernardino and the Peninsular Range.
Each sub-population faces its own challenge. Some are geographically small and isolated due to human barriers, such as highways in the Santa Monica Mountains. Others are limited by geographic boundaries, like the gnarly crest of the Sierra Nevada that divides two cougar populations.
To study and consider the health of the species in distinct geographic areas denotes a shift within state Fish and Wildlife from statewide species management toward regional management for ecosystem health.
“We’re starting to understand the important reality that we live in a big state, a diverse state — ecologically, politically, socially — all these things,” Dellinger said.
The department recently took a step toward regional management of mountain lions with a policy change to no longer automatically issue depredation permits to livestock owners in the Santa Monica and Santa Ana mountain ranges.
There, researchers with State Parks, universities and nonprofits found the sub-population to be genetically fragile. They became concerned when a mountain lion that researchers saw as essential to genetic diversity was killed under a depredation permit after it killed domestic animals.
“Depending on what our findings are, we might find there might be a need for additional changes to policy in different areas in the state,” Dellinger said.
Catching lions, testing scat
Studying a carnivore that can cover 40 feet in a single bound and leap 15 feet high from standing is no easy feat.
Since July 2015, Dellinger has worked with a Wildlife Services houndsman and his team of trained dogs that can track a faint scent for miles until a dog “makes the jump” to actually chasing and treeing a live lion. The dogs chase the mountain lion and the men chase the dogs, sometimes for days. Once treed, the men shoot the lion with a tranquilizer dart before taking measurements, gathering samples and attaching a radio collar.
So far, they’ve collared between 40 and 50 lions in the state.
In areas where hounds can’t be used, either because of environmental conditions or nearby residents, researchers use bait and a large trap instead.
It’s been the gold-standard for research. Catching and radio-collaring animals produces good information to learn how they move through the habitat and helps build a minimum population count. Tracks found in the field and lions documented by trail cameras can be compared to location data from a radio to identify other animals.
For Dellinger, who grew up hunting and fishing, the field work “is a heck of a lot of fun.”
But collaring lions is expensive, time-consuming and invasive — and funding isn’t available to do the work every few years to update a population count. So, researchers have turned to other methods of wildlife tracking to supplement the collaring efforts.
“One that has the most promise is using specially trained dogs to collect scat,” Dellinger said. “You can monitor genetics of the population, how inbred might they be, and diet, and monitor health — what kind of diseases or viruses these animals have been exposed to.”
He said he hopes researchers will circle back through the state every few years using the scat collection method — “like a traveling circus” — to keep tabs on regional mountain lion health.
Now, he’s still working to get the baseline population count using both methods. Field work is already underway on the Central Coast through 2018, and he plans to move on to the Peninsular Range in San Diego County in 2019 and then to the North Coast.
Correction: This story was updated to include correct data from the U.C. Davis California Roadkill Observation System.