As floods get worse, Britain tries a new solution: beavers

This beaver was released on Oct. 11, 2023, in Greenford, England, as part of the Ealing Beaver Project. A family of five beavers, two adults and three kits, was released into the 20-acre Paradise Fields nature reserve in West London, becoming the first beavers in the west of the British capital in 400 years. Dan Kitwood/Getty Images hide caption

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LONDON — Until two years ago, West London's Greenford Tube station used to flood whenever it rained heavily. The train tracks are aboveground, but the ticket office would often get inundated. Sandbags still line the corridor.

But in October 2023, a new family moved in nearby, determined to halt the water. The family members built their house from scratch with local wood and kept odd hours, sleeping all day and working only at dawn and dusk. They even put their young children to work.

A beaver swims in a pond after being released on Oct. 11, 2023, in Greenford, England, as part of the Ealing Beaver Project. The beavers that were released are part of an unlikely effort to bring back a vanished species and help Britain adapt to a very modern problem: climate change. Dan Kitwood/Getty Images hide caption

West London's Greenford Tube station used to flood whenever it rained heavily. The train tracks are aboveground, but the ticket office would often get inundated. Now, a nearby pond and wetland created by reintroduced beavers has helped mitigate flooding in the area. Sarah Tilotta for NPR hide caption

The beavers are part of an unlikely effort to bring back a vanished species and help Britain adapt to a very modern problem: climate change.

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Britain is famous for drizzle, but climate change is making rainfall heavier and more erratic . Places that didn't used to flood are now waterlogged. So scientists have enlisted some of the animal kingdom's best flood engineers — beavers — to help.

In West London, conservationists got a government license to resettle a family of five beavers in a 20-acre urban park near the Greenford Tube station. It used to be a golf course, with a creek running through it. Within weeks, the beavers dammed up the creek, creating a pond that holds water and stops it from spilling into the city. They also diverted the creek's flow into smaller tributaries, creating a wetland that better absorbs heavy rainfall — mitigating the risk of flooding downstream.

"They effectively turned this site into a giant sponge that can take heavy rainfall and slowly release water back into the landscape, creating a lot more resilience for flooding," explains Sean McCormack, a local veterinarian who started the Ealing Beaver Project , named for the London borough of Ealing, where it's located.

Scenes from the Paradise Fields nature reserve in Greenford, West London, where a family of five beavers has transformed what used to be a golf course into an urban wetland that helps absorb heavy rainfall and prevent local flooding. Sarah Tilotta for NPR hide caption

Sean McCormack, a local veterinarian, started the Ealing Beaver Project with Elliot Newton, a rewilding expert with the conservation group Citizen Zoo. Sarah Tilotta for NPR hide caption

Not only has the local Tube station stopped flooding, but the beavers have also coaxed back other species.

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"By felling trees, they've also opened up the canopy, and we've seen an abundance of biodiversity," McCormack says.

Freshwater shrimp have appeared in the creek, he says, plus eight new species of birds, two types of bats and rare brown hairstreak butterflies, which lay their eggs on blackthorn branches nibbled by beavers.

The beavers have also allowed the city to scrap expensive plans to dig a reservoir and levee.

"We said the beavers can do it for a fraction of the cost, certainly more sustainably," McCormack says.

A tour participant photographs the tiny white eggs of the rare brown hairstreak butterfly. Research indicates that the hairstreak may benefit from beavers nibbling on blackthorn, which encourages the new growth on which the butterflies prefer to lay their eggs. Sarah Tilotta for NPR hide caption

Commuters, tourists and recreationists enjoy hiking paths — and sometimes stop to watch the beavers in action — inside the Paradise Fields nature reserve. Sarah Tilotta for NPR hide caption

Now, joggers and teenagers stop to gawk at the beavers in action. There are guided walks and beaver safaris .

On a recent spring evening, a reddish-brown adult scampered in and out of the water, chomping on a felled willow tree. Eurasian beavers can weigh up to 65 pounds; this one was the size of a fat golden retriever.

The Ealing Beaver Project is one of dozens of sites across Britain where land managers are using beavers to restore wetlands and tame flooding.

But first, they had to bring them back from extinction.

Reintroducing beavers to Britain for the first time in centuries

In Britain, humans hunted beavers to extinction more than 400 years ago. By the early 20th century, only about 1,200 native beavers were left in Europe and northern Asia, surviving in parts of Norway, France, Germany, Belarus, Ukraine, Russia, Mongolia and China. Sweden reintroduced them in the 1920s, and other countries followed — part of a broader effort to restore native species.

By studying fossils, scientists determined that today's Norwegian beavers are genetically most similar to the beavers that lived in Britain centuries ago. So in 2009, wildlife officials relocated two Norwegian beavers to Knapdale Forest , a temperate rainforest in western Scotland. That pair, named Millie and Bjornar, became the Adam and Eve of the modern-day British beaver population. The Scottish forestry department calls them the "original beaver power couple."

"We became kind of attached to Millie and Bjornar," says Pete Creech, a forest ranger who remembers when they arrived, scrambling out of crates and splashing into a loch. He recalls their enthusiasm: "Lots of squeaking!"

Participants of a guided tour look at a dam built by beavers in a nature reserve in Greenford. Beavers build dams in part to raise water levels and hide underwater from predators. Sarah Tilotta for NPR hide caption

Oliver Hughes and his father, Michael Hughes, who traveled from North Wales to celebrate Oliver's birthday, keep their binoculars trained on the marshland, hoping to spot the resident beavers living at the Ealing Beaver Project. Sarah Tilotta for NPR hide caption

Creech set up hidden cameras to capture their crepuscular (dawn and dusk) movements. Within weeks, the beavers dammed up a tiny river, creating an enormous lagoon where swans now nest.

While the United Kingdom overall is getting wetter, some areas — including parts of Scotland — are getting drier, even seeing a growing threat of wildfires . Beavers ensure this rainforest stays wet and, thus, abundant. That's especially important at a time when wetlands are disappearing, with many drained for development.

"Wetlands are one of the most biodiverse habitats in the world," Creech notes. "The U.K. has lost over 95% of its wetlands, and now we're frantically trying to put them back."

Not everyone thinks rodents are the best way to do that, though.

A coot paddles through the marshland at the Ealing Beaver Project. Sarah Tilotta for NPR hide caption

Conflict with farmers

Unlike in London, where they're enclosed in urban parks, beavers in Scotland went forth and multiplied, spreading onto private land. Their numbers have been boosted by beaver bombers — renegade wildlife enthusiasts who've released unlicensed beavers into areas where they might not be welcome.

"As the beaver population has expanded, we've seen more [farmers] getting concerned," says Kate Maitland, a regional representative for Scotland's National Farmers Union.

Beavers can dam up irrigation channels, flooding crops.

"It's quite devastating to see acres and acres of your land sitting underwater," Maitland says.

Tom Bowser (left, with binoculars) is a fifth-generation Scottish farmer who runs beaver-watching tours, like this one in June 2024, on his farm near Doune, Perthshire, Scotland. Beavers were reintroduced in Scotland in 2009, after having been hunted to extinction. Andy Buchanan/AFP via Getty Images hide caption

They can also fell centuries-old trees and collapse riverbanks, exacerbating erosion. Maitland, a farmer's daughter, says she once got the full length of her leg stuck in a beaver burrow while walking along the banks of a stream on her family's land.

The Scottish government has set up a fund to rebuild riverbanks and other beaver damage, if repairs are in the public interest. That doesn't typically cover damage to private land.

Some farmers shoot beavers, though they need a license to do so, since beavers are a protected species . It's also illegal to disassemble beaver dams or lodges that are more than two weeks old. Instead, farmers are encouraged to call wildlife officials, who trap and relocate beavers. That's where London's beavers came from.

Other farmers have learned to like the new neighbors — and even celebrate them.

A beaver swims in a pond created by a beaver dam on Bowser's farm on June 16, 2024. Beavers were hunted to extinction across Britain more than 400 years ago and were reintroduced in 2009. Some farmers oppose the reintroduction: Beavers can dam irrigation channels, collapse riverbanks and flood crops. Andy Buchanan/AFP via Getty Images hide caption

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