Experts disagree on cougar population dynamics

An old female mountain lion with nubs for ears that apparently had frozen during a cold snap is captured and tranquilized by researchers on the C.M. Russell Wildlife Refuge in Montana. U.S. Fish and Wildlife Service photo

SPOKANE — Cougars have been in the news this summer.

A deadly attack in May near North Bend, Wash. A hiker dead in Oregon, likely killed by a cougar. In September, a girl near Inchelium, Wash., shot a cougar after the animal stalked her younger brother (see story, above). On Monday, a big cat was spotted in a tree in downtown Coeur d’Alene and eventually euthanized.

All these sightings, incidents and attacks have left many wondering, why? One common-sense answer: There must be more cougars.

Experts disagree.

“Well, I’m not so sure there are that many (more) cougars,” Brian Kerston said.

People often assume that if “we’ve seen a spike in the number of reports” there must be more cougars, Kerston said. But research he’s done doesn’t support that claim.

Kertson studies large carnivores for the Washington Department of Fish and Wildlife. For two decades, much of his research has focused on cougars. He’s found that the number of reported incidents is not directly connected to the overall cougar population.

“It’s totally counterintuitive,” he said.

Instead, what leads to cougar attacks, sightings and incidents has more to do with people and less to do with the animals.

That contradicts anecdotal evidence and statements by some wildlife managers. In a Tuesday Spokesman-Review article, Idaho Fish and Game biologist Jim Hayden said, “We’re seeing dispersal and seeing the range expansion of mountain lions in the West.”

“But I’m skeptical that they actually know that,” Kertson said. “Cougar populations are very, very difficult to enumerate outside of intensive field research. Those sort of assessments are made based on anecdotal observations.”

Instead, the rate at which cougars enter and inhabit human areas remains relatively steady regardless of the overall population, Kerston said. That finding comes from one of his studies in western Washington, near Snoqualmie Pass. The study has not yet been published.

Between 2004 and 2008, about 50 percent of the adult females Kertson studied survived. That number is “bad” and “indicative of a population decline,” he said.

And yet during that time, the “average cougar used residential areas 16 percent of the time.”

Compare that to 2013-17, when about 90 percent of female cougars survived. The average residential use remained more or less the same, Kertson said.

So, what is actually going on? There isn’t one simple answer, but three things may point observers in the right direction.

First, the number of humans has increased dramatically. Washington’s population has essentially doubled since 1990. That expansion inevitably increases pressure on cougar habitat.

At the same time, more people are recreating outside. That means even if people don’t live in cougar habitat, they are heading into cougar habitat on the weekends.

“Washington is so interesting because we really are the tip of the spear,” Kerston said. “We have a full suite of large carnivores. We have cougars. We have black bears. We have wolves. We even have grizzlies.”

The only other western states that can boast that kind of diversity are Idaho, Montana and Wyoming.

“Our human population is three times larger than those states combined,” he said. “We are the tip of the spear and we are going to continue to face these challenges moving forward.”

But still, what about the increased number of sightings, attacks and complaints? Anecdotal evidence, while perhaps not scientifically valid, still counts for something. Especially if you’re the one being stalked by an apex predator.

Kerston doesn’t doubt that people have been reporting more cougar sightings. But he believes that has more to do with the human brain and less to do with the cats.