Meadowbrook has 2 beavers, and they've been busy

Meadowbrook has 2 beavers, and they've been busy

URBANA – Along the Wandell Sculpture Garden trail at Meadowbrook Park is a special attraction, installed by nature's architect, the beaver.

The beaver dams on McCullough Creek are small but impressive. The first (upstream) is 35 feet across and about 6 feet wide. The water now, after all the rain, is 4 feet lower below the dam. The second, smaller dam is about 50 yards downstream. It is about 9 feet across and creates a 2-foot water level difference. Recent rains have left a good deal of standing and streaming water where it had been dry land two weeks ago.

Only a few people have reported seeing the beaver, and sightings have been only of a single animal, though there is speculation that the beaver, who moved in last year around this time, has possibly picked up a mate, said volunteer site steward and retired geologist Bob Vaiden.

"Beaver activity comes and goes at Meadowbrook. In the past, there have been quite a few beavers out there. I believe it was 10 or 15 years ago when I saw four of them," Vaiden said.

A recent spike in logging activity along the creek has raised the beaver's public profile. The large number of stumps and logs that bear the teeth marks of the beaver means many more visitors to the park are searching for and visiting the dam.

Urbana Park District project manager Derek Liebert said the visitors are unlikely to disturb the beaver since it's nocturnal.

"It's a dimension of wildlife viewing that visitors can enjoy. As they go out, I hope they will pay attention to the animal life that is present because the beaver is there. Frogs and ducks and wading birds have been attracted to the improved aquatic habitat that the beaver dam has created," Liebert said.

"A few footpaths have developed because of the interest in the beaver activity. We're not concerned about that, and we definitely are excited to get families coming out. The beaver is a keystone species, and in a lot of ways, the dam is improving the quality of the creek," Liebert said.

Illinois Natural History Survey mammalogist Ed Heske said beavers are more active in the fall, and that explains the sudden increase in trees being felled along McCullough Creek. He said the beaver is storing logs and twigs for forage and for dam repairs in the upcoming months. A beaver's survival may depend on its ability to maintain a stable water level over the winter, so it will stock supplies to repair possible damage to the dam, Heske said.

"The water level is important to the beaver for two reasons. Safety is one function. Beavers can swim underwater a long time and so not be exposed to predators. They will also make canals along the bottom of a pond or stream, so even if the water gets shallow, they can still be underwater," Heske said.

"The higher water level also maintains their refrigerator – their food storage. In fall, they cut down trees and put logs and branches down into the mud, and that keeps food soft and fresh through the winter. If the water freezes over, they just go into their underwater refrigerator in the mud where they've stored their food."

This beaver likely spends its days in a burrow in the creek's bank. The burrow may extend up to 20 feet into the bank and would be above water level, but the foot-wide entrance would be underwater, Heske said.

Some beavers have their lodges within their dams, but Heske said that isn't the case in Meadowbrook Park. Most beavers in Illinois dig burrows instead of building lodges, because the state is susceptible to random flooding that would wash out lodges, he said.

"This dam is too small and fragile to have a lodge in it, plus parts of it aren't high enough above water level to house a lodge. But the dam helps to protect the beaver's burrow by keeping water levels stable and keeping the entrance underwater," said Heske.

Vaiden said water levels all along the creek are higher, even below the dam where the beaver seems to have reinforced some natural blockages.

A beaver dam in this urban environment can interfere with manmade storm-water drainage systems.

Liebert said, "I do think it would be fair to say the city has some concern about the water level and the potential for water to back up in the storm sewer system, so we're working with the engineering division in terms of what levels are permissible."

If the water level should go higher than the city would allow, the park district does have a method for lowering the water, hopefully without harming the dam or displacing the beaver. This method, used by the district in the '90s with mixed results, involves securing a perforated PVC pipe into the dam at the desired water level in such a way that the beaver does not attempt to block it. Liebert said the goal would be to keep the beaver in the park.

Beavers at Meadowbrook Park aren't a new phenomenon, and not long ago they were treated as a nuisance. Bernie Sloan, a former board member and current member of the Champaign County Audubon Society, said he saw his first beaver dam in Meadowbrook Park more than 20 years ago.

"That was a different Meadowbrook Park back then – no paved path, no sculptures, no Prairie Play. I'd bet maybe two-thirds of the current prairie was cornfields. A couple of weeks later the city of Urbana engineering department moved in, ripped out the dam, and started channelizing McCullough Creek. From what I remember, they did it without the Urbana Park District's permission. The Urbana Park District stopped them when they found out," said Sloan.

Sloan said over the years he has also seen a beaver dam in the park breached due to rains, displacing the beavers.

The park district is closely monitoring the beaver activity on and around the creek. A single beaver can consume a good number of trees, but so far, this is not a concern, said Liebert. The district has caged certain high-quality trees like oak and hickory that it wants to maintain. But, Liebert said, the beaver has tended to go for the more opportunistic species of trees, especially silver maple, and has actually helped control some of the invasive plant species like autumn olive and honeysuckle that the district regularly removes.

Liebert said the district is concerned about a safety hazard posed by the sharp stumps the beaver makes, and district employees regularly remove sharp tips in areas where there is a lot of public use.

"Over the last year, I've had e-mail from a number of people asking about the beavers," Vaiden said, "and I've met a number of people out there looking for the pond and wanting to know where the dam is located. I think people are very interested and excited about seeing nature in action – this is something many have only seen on television programs.

"Having beavers has added quite a bit to the park. We'll have ducks, muskrats, and minks sometimes show up out there now. I do think it's a neat addition to the wildlife in the park."

Check it out

Judy Miller, environmental program manager for the Urbana Park District, said a visit to the Meadowbrook Park beaver dam will likely be included in a public program in the spring.

The Woodcock Walk (to observe the mating dance of the woodcock bird) at Meadowbrook is scheduled for 7 to 8 p.m. March 17.

For information, contact the Anita Purves Nature Center at 384-4062.

-