MNR offers ‘baffling’ solution to busy beavers around Crozier

They are the largest rodents in North America, they are almost completely blind, and although they are herbivores, they have been known to kill each other over territorial disputes.
They also are recognized world-wide as the national symbol of Canada.
But in Crozier, they are becoming a real problem to the roads department and landowners.
Alberton council has been considering a number of measures to mitigate the damage caused by beavers to low-lying pastures and woodlots, as well as culverts in the township.
At its regular meeting last Wednesday night, MNR senior technician Tony Elders presented council with an option that is showing considerable promise in controlling the problem of beavers.
That problem, said Elders, is the result of certain habits that are unique to beavers. “Beavers are the only mammals [other than humans] that modify their environment,” he explained.
The desire to build dams and flood large areas is the result of the beaver’s reluctance to stray more than 200 metres from water. Usually, they will not go more than 50 metres if they can help it.
That, and the fact they prefer to use trees that do well in wetlands, makes them want to build dams to extend their available territory.
Although they see poorly, beavers have excellent hearing and sense of smell. They can detect the sound of running water from a considerable distance.
In fact, it is running water that stimulates them to build—to plug holes. They prefer slow-moving water, of which there is an abundance in the district.
Elders said beavers will eat almost any kind of tree, but aspen is by far their favourite and aspens do well in wetlands. They prefer trees about four inches in diameter, but are capable of cutting and moving much larger ones.
Although nearly exterminated from the district in the last century, beavers are now back with a vengeance—and have become a concern.
Reducing their numbers is one option, Elders said. “The best thing to do is trap them,” he remarked, noting the local population can sustain up to a 30 percent loss per year without affecting their viability.
Elders said beavers raise three-four young a year, which usually disperse in their second year. They are monogamous and sometimes live in colonies, but will defend their territory fiercely against outsiders.
Where there are colonies, their collective efforts can result in large dams that significantly alter the water flow in their area.
But what about dams? Here, Elders had some bad news. He cautioned against destroying the dams since they can be a valuable environmental asset to other animals in the ecosystem.
That’s why it is necessary to seek permission from the Department of Fisheries and Oceans before destroying a dam—even on your own property—in case its destruction has an adverse effect on fish spawning beds and other sensitive areas.
There are other measures people can take, however. For instance, Elders said wrapping wire around target trees like aspen up to a height of four feet will discourage beavers.
As well, beavers don’t like evergreens, so if you plant a lot of them, they may move on.
But a new piece of low-technology is showing considerable promise in reducing flooding. Called the “Beaver Baffler,” it consists of a section of four-inch perforated weeping tile, a 20-litre bucket, wire, and some weights.
The Beaver Baffler is laid over the dam with each end submerged. The bucket goes on the side above the dam and the open end goes below. The whole thing is held in place by weights.
The device acts as a syphon and moves a tremendous amount of water over the dam undetected by the beavers because it is silent. Since they cannot hear anything and their eyesight is so poor, they may continue to reinforce the dam, but the water will flow unimpeded because they are not aware of the Beaver Baffler.
These devices are cheap, and easy to build and install. For further information on beavers and how to deal with them, contact Elders at the MNR office in Fort Frances.
He can be reached at 274-8628 or via e-mail at tony.elders@mnr.gov.on.ca

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