Never a Dull Moment - Profiling the North American Beaver
The North American beaver is a conservation success story. Now, how will we coexist?

“They’re ingenious, they’re single-minded, and they have all day long,” offers Stewardship Director Ian Sinks with a wry smile. It’s an apt description for a worthy adversary or a valuable ally, and it’s hard to tell which distinction Sinks has in mind as he recalls the North American beaver (Castor canadensis).

Above water, the beaver’s plodding, skittish demeanor belies its awesome ability to transform the surrounding landscape. These unassuming rodents are the original engineers of the American West.

Prior to European settlement, roughly 60 million beavers gnawed, dammed, and nested in nearly every watershed on the continent. Their dams continually reshaped river systems, turning rushing rivers into meandering streams—creating wetlands, slow-flowing channels, and ponds in the process. These temporary constructs infused ecosystems with nutrient-rich sediment while also offering perches for waterfowl and cover for juvenile fish.

By the 1820s, fur traders with the British Hudson’s Bay Company sought to ward off competition from westward-venturing Americans by depleting fur stocks across the Northwest. The company’s trappers swept through the Columbia River region, exterminating every beaver in sight. In just 25 years, beavers were nearly extirpated from the Pacific Northwest.

Fortunately, a decline in demand for pelts and proper management helped beaver waddle back from the brink of extinction. Today, their numbers range from six million to twelve million, and the beaver is widely heralded as a conservation success story.

A beaver nearly chewed through a Cottonwood tree at Pierce Island, Washington

A beaver nearly chewed through a Cottonwood tree at Pierce Island, Washington.

A funny thing happened along the beaver’s 20th century path to recovery, however. Americans tamed the West, installing nests and dams of their own, with a network of roads and cities to boot. They regulated the flow and direction of wild, flood-prone river systems. Humans supplanted beavers as chief engineers.

Today, a flourishing beaver population in the Columbia River region is creating crucial habitat while presenting new challenges where human and beaver designs overlap. Columbia Land Trust’s property on Schoolhouse Creek, a tributary of southern Washington’s Washougal River, is one such place.

A road crosses over Schoolhouse Creek, impounding water on the surrounding land, where nearby beaver activity contributes to ideal wetland conditions for juvenile Coho salmon. A culvert allows the creek and its fish to pass beneath the road. To local beavers, the culvert beneath the road represents a hole in an otherwise ideal dam. Activated by the sound of rushing water, the beavers have been doing their best to plug the culvert for over a decade. When successful, the resulting dam has a tendency to flood the road.

How exactly does one deter a beaver from its driving instinctual impulse? There are a number of tactics, and in recent years the Land Trust’s stewardship team has considered them all.

“Relocation is an option, but it’s not sustainable,” says Sinks. “There are at least a dozen beavers on the property and many more in the area. Any we’d remove would just be replaced.”

In 2011, the team installed a custom-built, metal fence around the culvert in the shape of a narrow triangle. This device, known as a “beaver deceiver,” is designed to present area beavers with a more complex and daunting dam project. The deceiver offers an innovative solution to the challenge of deterring beaver activity while still maintaining fish passage.

Beaver deceiver at Schoolhouse Creek, Washington

Beaver deceiver at Schoolhouse Creek, Washington.

Property owners across the region have employed these devices, along with trapping, relocation, and fencing to prevent beavers from flooding their fields and felling their trees. As the human population has increased throughout the Northwest, so have encounters with beavers.

At the same time, local agencies and environmental groups are exploring the potential benefits of beaver activity. Climate change and population pressures have led to dwindling water supplies, particularly east of the Cascades. Rivers that beavers once slowed with their dams now gush straight downstream at the first major snow melt, then dry up in early summer, leaving crops and livestock vulnerable to prolonged drought. Remarkably, the grandchildren of the ranchers who once drove beavers off their lands are now reintroducing beavers with the hopes of employing their engineering services.

In a recent visit to Schoolhouse Creek, stewardship coordinator Jeff Malone discovered that beavers had largely dammed the new perimeter established by the beaver deceiver. When considering the Land Trust’s next counter-maneuver, Sinks notes that only viable approach is maintenance. “We’ll make some tweaks to the deceiver, clean out the sediment and detritus, and keep at it.”

beaver dam

Beaver dam along a stream in the Lower Willamette region.

While it can be tempting to view beavers as pests in areas like Schoolhouse Creek, it helps to remember that we often share the same objective: to restore vital habitat in the Northwest. The primary difference between an invasive species and a naturalized species is that the latter gives back to its ecosystem. Not only do beavers benefit local wildlife, they might prove to be a crucial ally in addressing increased water scarcity.

Signs of beavers’ industry are everywhere, from verdant streamsides to mountain meadows. Its legacy is the Northwest itself. Back and forth, the beaver glides—meticulous and methodical—doing the thankless work of keeping lands wild.