Tribes plan overpass to help female grizzlies cross roads — and ecosystems (2024)

In a shady grove under the Mission Mountains, Payton Adams baited a small metal bear trap with a deer leg. The trap looked like a miniature Airstream trailer, with the deer leg at one end and a trap door at the other.

Adams is a wildlife biologist working for the Confederated Salish and Kootenai Tribes’ wildlife management program. He wanted to catch a bear so he could fit it with a radio collar and track its movements.

“What we try to do is get radio collars out on grizzly bears to better understand where they're moving, where they’re using the highway, where they're crossing, or areas where they're — unfortunately — getting hit along the highway,” Adams said.

Highway 93 is a major thoroughfare for the region that runs right through the heart of the reservation. A section of the road through the Ninepipe Wildlife Refuge is the deadliest strip of highway for grizzly bears anywhere in the Northern Continental Divide Ecosystem — a designated grizzly recovery zone in northwest Montana.

At least 19 grizzlies have been killed on that stretch of road since 2010. That's around a third of all grizzly bear deaths by vehicles across the entire ecosystem in that time.

“That type of stuff is exactly what we're trying to learn more about, in order to prevent it and to prevent further mortalities,” Adams said.

John Hooks | MTPR

The tribes in 2023 received a nearly $9 million grant from the federal government to build an overpass for wildlife across the most deadly 14-mile stretch of the highway. The immediate goal is to prevent fatal collisions — the larger goal is to open a pathway for breeding female grizzlies to reach separate populations of bears and unoccupied areas of their historical homeland.

The U.S. Fish and Wildlife service is currently reviewing whether grizzlies in the Northern Divide still need Endangered Species Act protections. The lack of movement and breeding between recovery zones was central to a federal court decision in 2018 that halted the government’s previous plans to propose delisting them.

Whisper Camel-Means leads the CSKT wildlife management program.

“We just really are trying to think about those females with cubs and having them be able to disperse across the landscape to maybe repopulate areas that they used to be and have been extirpated from,” Camel-Means said.

Take, for example, a legendary female researchers called “Bear 40.” In her lifetime she raised nine cubs and had 11 grandchildren. That’s the type of breeding engine that can really kick off population growth. But, a few years ago, Bear 40 was hit and killed by an ambulance the first time she attempted to cross the deadly section of Highway 93.

Biologist Michael Sawaya said researchers working to encourage grizzly bear travel need to think specifically about how females move.

“These females with cubs especially are, I think, worried about infanticide and about the potential for their own cubs to be killed by adult males,” Sawaya said. “And, I think that that drives part of their choice in crossing structure preferences.”

Sawaya said that, unlike males, female bears like a big, wide overpass and avoid tunnels. When an overpass can’t be found, he said they might just try to cross the open road — setting up the possibility for crashes and deaths like Bear 40’s.

Without females traveling and spreading out the gene pool smaller, isolated bear populations can dwindle.

“Eventually, they call it the ‘extinction vortex’ because those populations just keep spiraling out of control to the point where they aren't viable or they don't persist anymore,” Sawaya said.

The Northern Continental Divide population has reliable genetic exchange with Canadian bears, so it’s widely seen as the ideal source to provide that genetic diversity to isolated populations — like those around Yellowstone — and to kickstart new populations in the Bitterroot and Washington’s North Cascades.

The Ninepipe area on the Flathead has been identified as a key connectivity corridor for grizzlies moving southwest toward the Bitterroot. There, federal wildlife officials are weighing whether to manually relocate bears into the ecosystem or wait for them to make the move on their own.

Local and state governments in Montana and Idaho have said they prefer natural recolonization because it gives wildlife managers and residents more time to prepare for grizzlies' arrival and address potential conflict areas of food storage and livestock protection.

Whisper Camel-Means, with the CSKT wildlife program, hopes that, by creating a pathway for bears to recolonize the ecosystem, the tribes can help communities coexist with grizzlies, as they have done for millennia.

“They can't all just live here like it's a refuge,” Camel-Means said. “They need to be able to disperse. If we can just allow them to naturally move, I think people respond better to that than they do to relocation sometimes.”

The CSKT and Montana Department of Transportation are currently planning and designing the new overpass and other improvements to the Ninepipe highway section. Construction will begin next year at the earliest.