Problem encounters with cougars have increased in Oregon’s Willamette Valley.
National Park Service
A fatal cougar attack has reignited debates over hound hunting and cougar management in Oregon. Groups of Oregonians, particularly hound hunters, say that Oregon’s cougar population is growing out of control. Cougar advocates, on the other hand, say that Oregon is over-hunting cougars, which research suggests can lead to an increase in problem encounters.
But before you can figure out if Oregon’s cougars are being over-hunted or under-hunted, you need to know how many cougars there are in the state.
The Oregon Department of Fish and Wildlife estimates there about 6,600 cougars here, and possibly as many as 7,600. That’s three times higher than the numbers reported Washington or Idaho. It’s even slightly higher than the estimate for California: 4,000 to 6,000 cougars are thought to roam the massive state.
But hunting groups, ranchers and Oregonians who live in cougar country say the Oregon’s cougar count severely underestimates the state’s actual population. Conservationists argue it’s too high. Biologists and wildlife officials from other states say it’s a lot more complicated, and more than just a question of numbers.
One of the big reasons Oregon’s number is so much higher than its neighbors’: Oregon’s estimate includes kittens, which rarely survive to adulthood. Oregon does not count the juveniles of any other game species, like elk or bighorn sheep.
Two juvenile cougars hide on a fence to avoid territorial coyotes in Wyoming. Cougar kittens rarely survive to adulthood.
Lori Iverson / US Fish and Wildlife Service
“The fact that they don’t clarify themselves every time says that they want people to assume there are 6,600 big cats running around the state,” said John Laundré, a predator ecologist at Western Oregon University. “They don’t include babies for other ephemeral species, like ducks or deer.” And only adult animals can be hunted.
Derek Broman, ODFW’s state carnivore biologist, said whenever he gives a presentation he makes it clear that all ages are included in official population estimates. But there’s no mention of that on the department’s cougar webpage, and you have to look deep into the cougar management plan find adult cat estimates. A brochure specifies that the population includes all age classes, but never offers adult numbers.
Even if you exclude kittens and juvenile cougars from population estimates, Oregon still reports some of the highest densities of adult cougars in the country.
Washington’s research into cougar densities dates back nearly two decades and includes seven study areas. Across those areas, the state has documented consistent findings: Roughly two cougars for every 100 square kilometers, said Rich Beausoleil, the bear and cougar specialist at the Washington Department of Fish and Wildlife. He said Washington’s cougar-density numbers are consistent with what other studies — except Oregon’s — report.
Oregon Department of Fish and Wildlife’s surveys found adult densities twice that, depending on the ecosystem.
“I’ve not seen such high densities anywhere in the world,” said Rob Wielgus, former director of the Large Carnivore Conservation Lab at Washington State University, commenting on a controversial density survey conducted by Oregon.
Beausoleil has spoken to ODFW about the state’s population estimates before, and has criticized the design of Oregon’s studies, which he says will naturally overestimate regional populations. Derek Broman says ODFW controlled for overestimation and stands by their data.
It’s not unusual for cougar surveys to arrive at different conclusions, said David Stoner, a cougar biologist at Utah State University. Cougars are extremely hard to study because they’re so hard to find.
ODFW says these surveys confirm their statewide population estimates, which they calculate using a model. They estimate statewide density by mapping cougar deaths, and then add expected birth rates. They also tweak the numbers depending on food availability in the region.
Laundré said the growth estimate used in the study is an optimistic “best-case scenario” one: “A model is only as good as what you put into it. I could make their model show that there were only 3,000 total animals or 10,000 total animals.”
A tranquilized cougar is fit with a radio collar in California.
Harry Morse, California Department of Fish and Game
All of this might seem like an internal debate about the best way to count cougars. Everyone agrees that at one point in the 1960s there were only 200 or so cougars in the state, and today there are several thousand. The cats are in no danger of going extinct.
But a lot rides on accurate population estimates. Not only do these numbers tell management officials if populations are growing or shrinking, they’re used to help set hunting quotas for each region. Some scientists found that when cougars are over-hunted, problem encounters with humans and livestock increase.
Wielgus, who has left Washington for the Bend area, was one of the first to identify such a link.
“In the 20 years of research I did with WDFW, we conducted the largest study of cougars ever done anywhere. We found that heavy retaliatory killing or preventive killing actually causes increased problems,” he said.
It works like this: Female cougars have smallish overlapping territories that seem to fluctuate with prey abundance. Male cougars have larger, non-overlapping territories that encompass multiple female ones.
Only large, older males are capable of holding down these territories, “and you don’t get to be a 10-year-old male by attacking humans or livestock or pets.”
But Wielgus found that those 10-year-old males were far more likely to be killed by hunters. “And we found that when you remove an older male, you have two or three teenage males come in to take their place. And those are the ones that are responsible for most bad encounters between cougars and people, as well as the majority of livestock and pet depredations.”
This movement of younger animals also means it can be difficult to tell if a population is declining due to overhunting or staying the same.
Wielgus is a controversial figure in the predator management community, in part for research indicating that hunting wolves can increase attacks on livestock. He says he was silenced and forced out of his position at Washington State University because of his work.
A 10-month-old cougar is startled by a trail camera in the California mountains. The Oregon Department of Fish and Wildlife includes juvenile cougars in their total population estimates.
National Park Service
A smattering of papers have attempted to debunk his cougar research, but even more have supported it. One of the most recent was a massive, 30-year look at hunting and problem cougars in British Columbia. For their part, the Washington Department of Fish and Wildlife stands by Wielgus’ research and their own: Today, they manage cougars specifically to avoid the consequences of over-hunting.
“Our management philosophy is to manage for the social stability of the animal. We want to promote territoriality,” Beausoleil said.
WDFW’s data shows that when more than 14 percent of a cougar population is harvested in a given region, the population starts to skew young, territories dissolve, and problem encounters increase. To avoid this, they split the state into 49 game management units, and each unit allows 12 percent to 16 percent of cougars to be taken. When one of those units reaches that quota, it closes, and hunters can go to an adjacent unit. It’s not a perfect system: Sometimes, it can take a while to close a unit, and more cougars are killed.
At first glance, Oregon seems to be following Washington’s no-conflict guidelines: On average, Oregon’s hunters take less than 14 percent of the state’s big cats each year. But unlike Washington and Montana, where there are dozens of game management units used to set cougar quotas, Oregon’s cats are divided into just six large regions, which makes it more difficult to track regional densities.
The statewide quota for 2018 is 970 human-caused deaths — a whopping 27 percent of the state’s estimated 3,500 adults. Per the cougar management plan, the quota serves as a mortality cap, and not a target. The statewide quota has never been filled, but some of the game management units regularly approach theirs.
Zone A, which includes the region where the hiker was attacked, covers the North Cascades and the coast. As of Nov. 6, its humans have killed 167 of the 180 allowed cougars. ODFW estimates there were 989 cougars of all ages in Zone A in 2015. If half of those were adults, then roughly one third of adult cougars in the region were killed: Research suggests that’s a number high enough to cause conflicts with humans.
Overhunting cougars can have impacts on cougars’ societies, too. Once thought of as loners, recent research has revealed cougars’ social lives to be much more complex than previously thought.
Mark Elbroch, the director of the puma program at wildcat conservation organization Panthera, studies cougar communities. He’s found that the mountain lions within one male’s territory function like a society: They interact non-aggressively and seem to frequently share food, a favor that’s apparently returned in the future.
“You can imagine that overhunting will have huge impacts on these social networks and organizations, on the glue that holds them together as functioning groups,” Elbroch said.
A radiocollared cougar shares a kill with another cat, thought to be her cub. Cougars have been found to share kills with related and non-related cats, though they rarely eat at the same time.
National Park Service
And anecdotally, he’s seen the impacts of removing one large male from that society. After one of his study males was killed by hunters, he noticed a nearby male start to encroach on the old territory, just enough so that it crossed paths with a female and her two cubs. The female charged the strange male, and died. Her cubs lasted a little while, but eventually both died.
“One could argue that one bullet killed four mountain lions,” Elbroch said.
ODFW’s Derek Broman is dismissive of the “social chaos” hypothesis. He says the department has conducted its own research, and “there’s no information to suggest chaos and turmoil. Death and mortality is a common occurrence, even outside of human influence.”
Oregon officials may dispute the idea that their management practices lead to more problem cougars. But the state does remove more such animals than neighboring states. In 2017 there were 462 such complaints, and 175 cougars were killed. Those numbers remain fairly stable from year to year, though they’ve risen dramatically in the Willamette Valley.
In comparison, about 100 cougars are killed in California each year for attacking livestock. In 2016, 46 nuisance cougars were killed in Washington.
Hunters say that the best way to combat these problem cats is to increase hunting. But unless a large number of cougars are removed over a large area, more will just move in to take their place. Which is why some are calling for a return to hound hunting.
The theory is this: Hound hunters, unlike normal hunters, can be selective. If their dogs tree a cougar, the hunter can choose if it’s going to be a worthwhile trophy. If the animal is small or female, the hunter can pull their dogs off the tree, and the cougar can live.
This, say hound hunting advocates, creates a population of scared cougars, who will run away as soon as they hear a human in the forest.
Laundré and Elbroch are skeptical that hound hunting leads to scared cougars, but other biologists think it’s not impossible.
“Hound hunting doesn’t have to be a lethal pursuit,” Stoner noted. “You have the ability to pursue multiple animals over the course of a season, and can in theory select a nice tom.”
Unfortunately, that selectivity targets large toms: the exact animals many biologists say are necessary for maintaining cougar social stability. Indeed, when hound hunting was banned in Oregon, the average age of cats killed dropped.
In the end, biologists say it’s important to remember that the only way most people will ever interact with a cougar is through their livestock or pets. “Cougars aren’t fearsome,” said Laundré, who has tracked and collared more than 250 cougars. “I’ve never had a cat behave aggressively.”
As Teddy Roosevelt noted after chasing a cougar with hounds and stabbing it to death, “He was more afraid of us than the dogs.”