Beavers are natural engineers in the landscape, creating wetlands out of streams, and providing vital habitat for a myriad of plants and animal species. Although beavers were once largely eliminated from much of North America during European colonization, they have now rebounded. Conflicts between beavers and humans inevitably result as beaver move into areas where they had been absent and begin damming waterways. Luckily, simple solutions are available to help us co-exist!
Question: Why Do Beaver Modify their Habitat?
Answer: Beavers move poorly when out of water. To compensate, they create a water-surrounded world to protect themselves from terrestrial predators and to stay close to their food source. Security and easy access to various food plants close to water’s edge are made possible by the beaver dam. Created to raise the water to the level which best suits the beavers’ needs, the beaver dam is the key to food and safety for the beaver colony.
The most noticeable change in the landscape, besides the dam, is the beaver lodge. This mound of sticks rising out of the water is dry inside and may house as many as ten beavers. Most importantly, the beavers take advantage of the raised water level to deny access to virtually all potential predators; their lodge can be entered and left only through the water!
Less obvious to the un-trained eye is the beaver’s use of water for food storage. As strict vegetarians, they feed on the bark, twigs, leaves and roots of various plants, favoring birch, alder, aspen, apple and willow, cattails and lily pads. Beavers fell trees and then float the logs and branches for use as construction materials or for their winter food cache. Looking like nothing more than a pile of sticks and branches lying in the water, food caches may be as large as 8 feet wide and 40 feet long and will sustain the beaver colony until spring.
Beaver Family Life
Beavers mate for life, and average 4 kits per litter. The young kits spend much of their early days in the lodge before swimming with their parents and learning beaver skills. They are slow learners and spend two winters with their parents before dispersing, thus a beaver colony may contain kits from both the previous and current year. Although beavers are largely nocturnal, the migrating 2-year olds are sometimes seen during daylight as they begin to seek out new territory. This journey is fraught with hazards such as cars, dogs and coyotes. Even their own species can pose a risk, since adult beavers are very territorial and aggressively drive out interlopers.
Question: Why Doesn’t Trapping or Dam Destruction Work?
Answer: Where there is beaver habitat, there will be beavers. In one study in Tennessee, after all 169 resident beavers were removed from a wetland study site, 162 new beavers moved into the area within a few years. Migrating 2 year-olds in search of new territory often replace any trapped beavers, occupying vacated lodges and building new dams. It’s no surprise that many landowners perceive trapping programs to be ineffectual.
Destroying dams doesn’t work because beaver have an instinctive response to patch up any spot where they hear the sound of running water. They persistently rebuild their dams and foil efforts to discourage them. There are no long-lasting ways to discourage beaver from occupying suitable habitat. The answer is to work WITH the beaver to control flooding, and luckily we have solutions to help cities, towns and homeowners do just that!
Solutions to Flooding Problems
Water flow control devices are an effective way to solve flooding problems due to beaver activity. Beavers are stimulated to repair breaches in their dams by the sound, feel, and sight of running water. Water flow control devices work through deception and exclusion – pipes are inserted through beaver dams in a way that the beavers don’t realize that their dam has been breached, and then fenced off so beavers can’t plug them.
As shown in the diagram below, the system involves inserting 30-foot sections of perforated flex pipes (8″ in diameter) through the dam to allow water to flow through unbeknownst to the beaver. A square cage around the inlet end of the pipes (the end that water enters through) prevents the beaver from being able to plug the pipes with debris.
Question: Can I install a water flow control device myself?
Answer: We always recommend working with an experienced installer when installing a water flow control device because the effectiveness of the flow device is largely dependent on it being properly installed. Most complaints about the flex-pipe system “not working “ usually involve a problem with the application, not the technology!
Question: Where does the flex-pipe system not work?
Answer: This system won’t work in less than 1 ½ feet of standing water (the pipes fill with silt) or in areas where a large volume of water must be moved, such as under bridges. Very narrow bodies of water can also be problematic, as it is difficult to prevent the beaver from moving downstream and building secondary dams.
Question: How Do I Protect Vulnerable Trees from Beaver Damage?
Answer: Beaver are uncomfortable travelling far distances out of water, so you need only focus your efforts on the beaver-preferred trees (birch, alder, aspen, apple and willow) within 100 feet of the shore.
The simplest solution is to go to your hardware store and purchase a roll of heavy gauge wire mesh (4 feet high with 2″ x 4″ mesh squares) and wrap it around a tree, securing the two ends with form wire so that a cylinder of mesh is free-standing around each tree. Leave 5″-6″ of space between the tree and the wire. There’s no need to stake the wire in place since the beaver will not go under it as long as it’s flush with the ground at the bottom.
If aesthetics are a concern, you coat tree trunks with a sand and paint mixture. To do so, mix 8 ounces of fine sand (30 mil, 70 mil or mason sand) with one quart of oil or latex paint. Stir the mixture often, and paint trunks about four feet high. The paint can be clear or color-coded to match the trees. Avoid painting young trees less than about six feet tall as this may be harmful.
For more information on Beavers, please visit WildLifeHotline.org.