Following the tribal blessing, the family group is released into the waters of Tásmam Koyóm in Plumas County, California on October 18, 2023. Opening the beaver kennels, from L-R, are: CNRA Secretary Wade Crowfoot, CDFW Director Chuck Bonham, Maidu Summit Consortium Chairman Ben Cunningham, Occidental Arts & Ecology Center Co-directors Kate Lundquist and Brock Dolman, University of Minnesota Asst. Professor/researcher Dr. Emily Fairfax, CDFW Beaver Restoration Program Manager Valerie Cook, and Tulalip Tribes of Washington beaver biology/Utah State University graduate student Molly Alves. (CDFW Photo/Travis VanZant)

MONGABAY: When does beaver reintroduction make sense?

By John Cannon, Mongabay

KEY IDEAS:

  • California has recently relocated beavers from spots where they were causing problems, like flooding, to tribal lands in Northern and Southern California.
  • Many advocates say that relocating beavers to areas where they once existed brings back “ecosystem engineering” benefits to the landscapes they live in.
  • But experts also caution that while beavers can help with fire resilience and improve water quality, they are only part of broader solutions to climate change and watershed restoration.
  • Beaver advocates also note that learning to coexist peacefully with beavers is critical, both for the recovery of the species and for the ecosystem services they provide.

“It’s a little wet!” Ben Cunningham shouted over his shoulder as he slipped knee-deep into one of the unseen rivulets spidering through the hip-high grasses and willow galleries around us. Up until that point in our walk, Cunningham had been agreeably taciturn, contemplative about the return of this meadow to the Mountain Maidu people in recent years, and their efforts to bring beavers back as part of the tribe’s work to restore its health.

“Next time, you’ll have to bring your boots,” he said, chuckling over the din of rushing water that seems to be both everywhere and nowhere under a thicket of green peppered with yellow-eyed, purple-petaled asters.

Above, a young osprey circled in low loops above our heads. The bird dropped periodically, flying past dragonfly armadas, their abdomens glowing orange in the August sun.

Our feet thoroughly soaked, we came upon a mound of sticks and mud nearly to eye level: a lodge. It had taken this beaver family a little less than a year to build, said Cunningham, a Mountain Maidu elder and chair of the nonprofit Maidu Summit Consortium. They’d been released here in 2023, California’s first beaver translocation in decades.

The meadow was once mostly dry. Each year, mountain snowmelt in the spring and summer carved deeply gashed “incised” creeks through this landscape, allowing the water to run swiftly through the meadow and on downslope toward the Feather River.

Today, meltwater from the ridges at the northern end of the valley flows into the beaver pond, slowing its gravity-hastened hurry and spreading it out on Tásmam Koyóm, as the Maidu call the meadow. Even in late summer, clear, burbling streams meander out from the pond.

By curbing the rush of water from the heights with their dams, beavers can help lower fire intensity, create habitat for plants and animals, and blunt the effects of droughts.

“They are really powerful ecosystem engineers,” Emily Fairfax, an assistant professor of geography at the University of Minnesota, told Mongabay. “The number of services they provide to us and ways that they build resilient landscapes is honestly too much to just rattle off all at once.”

Two beavers await release at Tásmam Koyóm, a Mountain Maidu meadow in Northern California.
Two beavers await release at Tásmam Koyóm, a Mountain Maidu meadow in Northern California. Image courtesy of CDFW.

Correcting history

Until recently, though, California didn’t even acknowledge that the North American beaver (Castor canadensis) had long ranged widely throughout the state, much less the positives that the animal’s “ecosystem engineering” can provide, particularly in a warming world. Beavers had nearly been killed off for the fur trade by the mid-1800s, and afterward, scientists insisted that the animal was only native to a narrow strip of low-lying habitat. What’s more, the few that remained were often harassed for the problems they caused, real and imagined, for human agriculture, engineering and settlements.

It took an amalgam of advocacy, education and corrections to the scientific record to set the stage for their return to parts of their historical homeland, like eastern California’s mountains. In the mid-2010s, the Mountain Maidu joined that movement.

Beaver advocates had begun to rack up successes, including a state beaver restoration program. California’s policies on dealing with “problem” beavers shifted dramatically, favoring coexistence over lethal control. In the meantime, the Mountain Maidu had prepared Tásmam Koyóm, installing dozens of structures that mimicked beaver engineering.

“They had done a lot of pre-restoration work,” said Valerie Cook, the program manager for the California Department of Fish and Wildlife (CDFW). “We knew that the habitat was, for the most part, just ready to receive and support beavers.”

In an April 2025 report on the beaver restoration program, CDFW notes the success at the Tásmam Koyóm site, crediting the beavers for increasing the surface area of water at the release site by more than 22%. The release seemed to be a turning point for the state’s once-contentious relationship with beavers.

California is a poster child for the impacts of climate change — a state beset by shifting weather patterns that bring inconsistent snowfalls and years-long droughts. Many of its forests teeter on the edge of destruction, wherein a single spark could ignite yet another record-breaking fire. And the state must simultaneously muster — and store — enough water from often-scant annual precipitation for both the U.S.’s largest population and a yawning expanse of hydrologically intensive agriculture.

Researchers emphasize the role of beavers in buffering watersheds against the effects of climate change.
Researchers emphasize the role of beavers in buffering watersheds against the effects of climate change. Image courtesy of Jordan and Fairfax, 2022 (CC BY 4.0).

Beavers can play a big role in softening the repercussions of climate-related problems. But the pilot project at Tásmam Koyóm demonstrates that they’re only a part of the solution.

“We’re always going back to the whole systems piece, honoring beaver for the work beaver can do, but not turning them into this silver bullet,” said Brock Dolman, an ecologist and co-founder of the nonprofit Occidental Arts and Ecology Center in Sonoma County.

For more than two decades, the center has advocated for harmonious coexistence with beavers in California as a piece of restoring the state’s watersheds. In that time, a “beaver fever” has bubbled up, remaking the beaver’s image from a hydrological pariah into a climate savior without equal, one whose return can heal the land and the past displacement of humans and beavers alike.

The reversal in perceptions has spawned debate in the advocacy community: Yes, moving beavers can spare them from being destroyed if they’re causing flooding or cutting down trees in places that wreak havoc. But are we asking too much of them?

“I think we’re in kind of an idyllic [stage of] beaver literacy,” advocate Heidi Perryman said. “People have begun to hear a lot of good things about beavers, and they’re very hopeful that beavers can fix everything that we’ve messed up.”

But the view of this animal as wholly positive is “no more accurate” than earlier beliefs that they’re always a nuisance, Perryman added.

CDFW staff move a family of seven beavers close to the release site at Tásmam Koyóm in 2023.
CDFW staff move a family of seven beavers close to the release site at Tásmam Koyóm in 2023. Image courtesy of CDFW.
Beavers like this one, on Mountain Maidu land, are bringing back an animal that was killed as a pest species and trapped to near-extinction for the fur trade.
Beavers like this one, on Mountain Maidu land, are bringing back an animal that was killed as a pest species and trapped to near-extinction for the fur trade. Image courtesy of CDFW.

How do you solve a beaver problem?

Perryman, a child psychologist in the San Francisco Bay Area town of Martinez, calls herself an “accidental beaver advocate.” When a pair of beavers turned up in Martinez’s Alhambra Creek in 2006, town leaders wanted to get rid of them for fear that their dams would cause flooding.

But Perryman was taken with Martinez’s new rodent residents, and she wasn’t alone. A groundswell against killing them surged, and the beavers stayed.

Perryman reckons that, for years, she spent five hours a week watching the beavers after their arrival in Martinez, learning about their behaviors, discovering their personalities, and eventually documenting more than two dozen individuals. She posted blogs, photos and video on a website linked to the nonprofit she still leads, Worth a Dam.

As the beavers changed the watershed with their engineering, other wildlife flourished, Perryman said. “We had mergansers and heron and otter and mink, things that we had never seen in our creek before because of the dams that beavers maintained.”

The town is seen as a model for coexistence, and it still hosts an annual beaver festival even though the beavers have moved on, no longer living in Martinez.

Now, with two pilot relocations –– the one to Tásmam Koyóm and another on the Tule River Reservation in Sierra Nevada foothills that began in 2024 –– there’s another tool that sidesteps the lethal removal of beavers that come in conflict with humans.

Though exact numbers are hard to come by, Perryman estimates that the state allows killing of 1,000 to 3,000 beavers each year through the “depredation permits” CDFW issues to landowners when beavers cause damage, according to her public records requests.

“It’s still remarkable how many times California turns down the opportunity to coexist with beavers,” Perryman said.

A beaver noses out of its crate at Tásmam Koyóm, a return to its historical habitat.
A beaver noses out of its crate at Tásmam Koyóm, a return to its historical habitat. Image courtesy of CDFW.

No one knows the exact number of beavers living in California, but scientists figure that North America is home to 10 million to 15 million beavers, an extraordinary recovery for a species hunted and trapped to near-extinction. They numbered at least 60 million and perhaps as many as 400 million before they were targeted for their fur.

Perryman said she understands why moving beavers is so enticing.

“It really appeals to people because it’s so much nicer to relocate things than to kill them,” Perryman told Mongabay. But, she added, “It’s really important for people to do relocations thoughtfully and carefully … It’s not without risks.”

Relocation: An ecological solution or a last resort?

Rather than concentrate on those risks, Perryman said, the focus today is more often on how beavers can help, which can be rife with unrealistic expectations. That view has made her skeptical of California’s translocation efforts.

“You don’t get to relocate beavers and have them stay just where you want them or have them only build dams where you want them or have them only take the trees you choose for them,” Perryman said. “They do their own thing, and our fortune is that we can be smart enough to learn how to coexist with them and [benefit from them].”

Most experts agree that finding ways to live with beavers should be the primary aim, before trying to move them.

“Translocation is kind of the final piece,” the OAEC’s Dolman said, “if and when you’ve exhausted everything [else].”

R. Kyle Pagel, a scientist with the state’s beaver restoration program, echoes that sentiment. CDFW starts with encouraging coexistence strategies when there’s conflict, such as coating tree trunks with sand-containing paint to discourage beavers from cutting down trees.

Only after those efforts fail should relocating the beavers — or killing them — be considered. The answer is, in part, pragmatic: The thinking is that once they’re gone, the “problem” is solved, but a spot that’s suitable for one family of beavers is apt to attract another, Pagel said.

“Most likely, it’s just a matter of time before a new group of beavers moves in and causes conflict again,” he added.

As part of the beaver restoration program, landowners, NGOs and even federal agencies can follow in the footsteps of the Mountain Maidu and the Tule River Tribe and request to have beavers moved to their land. But before that happens, it’s critical to evaluate any unintended consequences to infrastructure or neighbors, Pagel said, as well as whether the animals are likely to stick around long enough to bring some of the intended benefits.

“The last thing we want to do is then proceed to translocate them to a brand-new site, and then have conflict again,” he added. Still, Pagel acknowledged, “We’re not going to be able to conduct enough translocations to take care of every beaver conflict.”

Three beavers from a family of seven take their first swim at Tásmam Koyóm in 2023.
Three beavers from a family of seven take their first swim at Tásmam Koyóm in 2023. Image courtesy of CDFW.
Beavers build lodges like this one at Tásmam Koyóm that have underwater entrances, offering shelter from the elements, a safe home for kits, and food storage.
Beavers build lodges like this one at Tásmam Koyóm that have underwater entrances, offering shelter from the elements, a safe home for kits, and food storage. Image by John Cannon/Mongabay.

Perryman highlighted her concerns about the Tule River Reservation release in a letter to CDFW that she shared with Mongabay. The wildlife agency concluded that the beavers released there in June 2024 were likely killed by predators — probably black bears, or wolves from the Yowlumni Pack that first turned up near the reservation in 2023.

Perryman said more should have been done, such as making sure the entrances to the temporary lodges provided were underwater, to give them a chance to escape from predators and allow them time to adapt to their environment.

“We put beavers in places without safe places to hang out,” she said, “and basically, we created a bear-feeding program.”

The two reintroduction pilot sites — on the Tule River Reservation in Southern California and Mountain Maidu land at the northern end of the Sierra — differed in food availability, water levels and the presence of predators. That likely contributed to the divergent outcomes, said CDFW’s Valerie Cook.

Now, the goal is to improve relocations at these sites and beyond. Experts say they’ll use “the best available science” to pick out places that would benefit from beavers, as well as when, how — and if — to relocate them.

The “challenge” of the initial releases hasn’t stopped the tribe from learning what to do better next time, said Kenneth McDarment, a Tule River tribal citizen and former member of the tribal council.

He said they’ve visited the Tulalip Tribe in Washington state, known for their successful beaver reintroductions, and worked to identify new release sites with enough food and adequate water depth to allow the beavers to dodge predators.

“Success will be a healthy population that’s thriving and reproducing through our watershed,” McDarment said..

‘Partnering with nature’

Researchers like Emily Fairfax say they want to return more beavers to their historical range. The animals once lived across much of the state, but rampant trapping for fur markets up through the beginning of the 20th century “ruined beaver populations,” Fairfax said.

“I think we owe it to the beavers to do whatever we can to help them reestablish in the watersheds.”

In the past several years, a bevy of research has documented the impacts that beavers’ presence can have: dampening the effects of drought, sequestering carbon, generating habitat for other species, and buffering the landscape against high-intensity fires, as detailed in a paper Fairfax co-authored with the title “Smokey the Beaver,” published in the journal Ecological Applications.

“The fires are getting worse. The droughts are getting worse. We need to figure out how to make our rivers healthier,” Fairfax said. “There’s a huge amount of data showing that beavers do work, so let’s just do it.”

California’s beaver restoration program “has taken a really positive step” in finding ways to reintroduce beavers, Fairfax said. Still, she added, “I think we should be ramping up much faster than we are right now, because the scale of environmental challenge we have is really, really high, and it’s such a low-hanging fruit to just let beavers exist.”

That points to the importance of reintroduction, even with the types of challenges that arose on the Tule River Reservation, she said.

Fairfax was present for both pilot releases at Tásmam Koyóm and at the Tule River Reservation, and she acknowledged the sadness of knowing translocated beavers have died. “I understand that, but also the predators need food too,” Fairfax said.

Pagel noted that many of the translocated beavers come from the valleys carved by the Sacramento and San Joaquin rivers. They probably didn’t live alongside predators like bears, wolves and mountain lions, and inhabited more temperate climates than what they experience in the mountains. Tásmam Koyóm, where the first family was released, sits at nearly 1,500 meters (5,000 feet) above sea level.

“I would be shocked if they’ve ever seen snow,” Pagel said. Nor had they likely ever had to store up food for harsher winters, he added. But, somehow, the family survived that first year.

Fairfax also noted that expecting that all relocated beavers will survive is unrealistic. For one, it doesn’t take into account what would have happened to beavers that are in conflict with people. “All of them would die if we did nothing,” she added.

A beaver kit hitching a ride on the tail of its older sibling to rejoin the rest of their family in exploring their new habitat.
A beaver kit hitching a ride on the tail of its older sibling to rejoin the rest of their family in exploring their new habitat. Image courtesy of Brock Dolman/OAEC.

Given a chance, Fairfax said, beavers can adapt, if not always in predictable ways. She was a physicist before diving into the watery world of beaver ecology, and she said pinning their behaviors down is next to impossible, from the materials they use for their lodge to their choices of food. “They break every single rule,” she said. “You can’t write a law to describe them.”

A big part of the problem is shifting our approach from controlling nature to partnering with it, she added. “We dammed the Mississippi. We’ve built levees. We’ve dammed the Colorado. We know how to control nature,” Fairfax said. But teaming up with nature is “a lot harder.”

“Working with beavers requires letting go of some control,” Fairfax added. “It will be messy and frustrating.”

A dose of sovereignty

The beavers released on the Tule River Reservation in 2024 unearthed some of that frustration when they didn’t survive. But hundreds of miles to the north, where the granite of the Sierra Nevada gives way to the volcanic Cascades, the beavers brought to Mountain Maidu land are thriving, apart from two deaths attributed to lung infections.

While the focus is now on restoration, the quest to reclaim Tásmam Koyóm has a long history. The Mountain Maidu were pushed out of this valley nearly two centuries ago. But the land still bears the signs of the Mountain Maidu’s forebears, as well as the beavers. Centuries-old beaver dams have been excavated in the meadow. And exposed bedrock there holds 112 cup-shaped mortars where Maidu ancestors once pounded the acorns that provided them with countless meals.

In 2019, four years before the beavers were brought back, Tásmam Koyóm was returned to the Mountain Maidu.

“That was a good feeling, [to] get something we can work with and be proud of … make it back like it used to be,” Cunningham said, as he took in the verdant meadow.

The paired returns of the beaver and the Maidu bring not only a renewed partnership with nature, but also a measure of “tribal sovereignty” to the people who have long cared for these spaces, Fairfax said.

“These are independent nations that have had beaver … and for a long time, they couldn’t get them because of California’s policies,” she said. “If nothing else, this is helping restore an animal to a people that have lived alongside it a lot more sustainably than most Californians have.”

A kit peers up at the camera in Martinez, California.
A kit peers up at the camera in Martinez, California. Image by Heidi Perryman/Worth a Dam.

Not far from where Cunningham and I stood next to the dam, a tribal work crew was busy clearing away the young conifers that bristled in “lodgepole alley” on the meadow’s periphery, an arduous effort to temper the risks that more frequent and intense fires pose to this landscape. The blisters, sweat and — on the day I arrived, bee stings — the crew endures are a testament to their commitment to complementing the work of the beavers. And in this case, it seems, they’re restoring resilience, not only to Tásmam Koyóm, but to a people.

For Cunningham, the work is a celebration, the reuniting of two ancient family members: the Mountain Maidu and the beaver. And it’s part of what brings Cunningham back to Tásmam Koyóm, day after day.

“It’s just great to be out here, to have something to work for, be proud of,” Cunningham said. “It’s your own.”

John Cannon is a staff features writer with Mongabay. Find him on Bluesky and LinkedIn.

This article was first published at Mongabay.

Citations:

Aubry, S. C. V., & Sistla, S. (2025). Beaver dams mitigate the impacts of whiplash weather in a fragmented habitat: A Salinas River case study. The Journal of Wildlife Management. doi:10.1002/jwmg.70081

Jordan, C. E., & Fairfax, E. (2022). Beaver: The North American freshwater climate action plan. WIREs Water, 9(4), 34. doi:10.1002/wat2.1592

Willby, N. J., Law, A., Levanoni, O., Foster, G., & Ecke, F. (2018). Rewilding wetlands: beaver as agents of within-habitat heterogeneity and the responses of contrasting biota. Philosophical Transactions of the Royal Society B: Biological Sciences, 373(1761), 20170444. doi:10.1098/rstb.2017.0444

Fairfax, E., & Whittle, A. (2020). Smokey the Beaver: Beaver‐dammed riparian corridors stay green during wildfire throughout the western United States. Ecological Applications, 30(8), e02225. doi:10.1002/eap.2225