Beaver Fever! Sherri Tippe gives a dam about Colorado's beaver population

A beaver in its natural habitat.
A beaver in its natural habitat. Getty Images

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It takes Tippie and Niffen only a few minutes to set three traps at the edge of turbid Toll Gate Creek. By tomorrow morning there will be three beaver in them. The rest of this family of six is already at her house, waiting for the trip south.


A few weeks ago, Rick Spowart, the state's district wildlife manager for Estes Park, invited Tippie to tour a series of beaver dams and ponds along Fish Creek, on the southwest side of town. Although the creek winds mostly through private property, the beavers' work is only a few feet from a major road and a public right-of-way, where the Estes Valley Recreation and Parks District plans to build a 2.4-mile, $850,000 compacted gravel trail for bikes, pedestrians and horses. One of the dams, in fact, stretches a few feet into the path of the proposed trail.

By the time Tippie arrived, the meeting had been moved to the Estes Park Town Hall to accommodate public interest. What had started out as an informal gathering of Spowart, Tippie and the contractor had mushroomed into a hearing that drew dozens of locals, many worried about the beaver being chased from their homes by, ironically, a project financed largely through lottery proceeds from Great Outdoors Colorado. EVRPD executive director Stan Gengler was eager to reassure them.

"We don't want to see the beaver moved," Gengler said. "We think they are an environmental asset to the trail."

When it was her turn to speak, Tippie stood up in a T-shirt that said "Dam It!" and stressed the need to come up with a "gentle" way to proceed. "Bulldozers scare the snot out of me," she declared. "These beaver are exactly where they belong."

The dam that crosses the trail is some distance from the lodge and the main pond, she pointed out, so it shouldn't be difficult to come up with a solution that wouldn't disrupt the beaver activity. Perhaps, she suggested, signs could be put out to inform trail users about the beaver and urge them to keep away from the dams. By the time she finished, the contractor was considering placing a cantilevered walkway on pylons over the dam, as well as fencing and signs to keep people from trespassing on the beaver habitat.

Such a chain of events would have been hard to imagine a few years ago: that a state wildlife officer would think it was a good idea to consult Tippie; that the fate of a few feet of beaver dam would become cause for public concern in Estes Park; that the people behind the bulldozers would be so eager to appease the folks who usually stand in front of them. Tippie isn't used to cooperation on that scale.

Yet her work is increasingly about building such alliances. Much of her energy in recent years has been devoted to persuading government agencies and property owners to leave the beaver and their projects in place. Last May she supervised the installation of a "Castor Master" in a magisterial beaver dam spanning Bear Creek, just off Hampden and Harlan in southwest Denver.

A Castor Master is a large section of polyethylene pipe that's inserted into a dam beneath the water level and caged at each end, to keep the beaver from plugging it up. It insures a certain flow of water from the pond and discourages the beaver from building the dam any higher. The contraption is one of several inexpensive flow devices that make it easier for humans and beaver to coexist. The one on Bear Creek was the second that Denver Parks and Recreation has approved, and a team of Tippie's volunteers, including Clayson and Gasser, struggled alongside Parks and Rec ecologist Ashley DeLaup to make sure it was properly placed. Water officials from two other counties observed the process and picked up additional information from Tippie, who hopes to see more of the devices used in other conflict areas.

The Castor Master installed that day seems to be meeting the needs of the beaver as well as those of the Urban Drainage and Flood Control District, which likes to see the flow in Bear Creek unimpeded. "A lot of dams got flooded out this summer, but not this one," DeLaup says.

A wildlife camera installed on the lodge has captured a motley procession of visitors in the area: coyotes, red fox, raccoons, geese, muskrats. The site presents a terrific opportunity for field trips for Bear Creek High School students and others who want to study a mini-ecosystem, DeLaup says: "A dam like this creates a new urban wildlife viewing area. It also allows us to take advantage of some of the things that make beaver a keystone species. They're raising the water table, so we'll have more plant growth. And as they cut down trees, you'll start to get an understory, a whole new type of habitat."

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Alan Prendergast has been writing for Westword for over thirty years. He teaches journalism at Colorado College; his stories about the justice system, historic crimes, high-security prisons and death by misadventure have won numerous awards and appeared in a wide range of magazines and anthologies.
Contact: Alan Prendergast