Overview of Damage Prevention and Control Methods
- Remove dams (may require state permits)
- Remove trees and other sources of food
- Install flow devices to control water levels
- Install metal fences around individual trees
- Install fences to protect culverts
- Nothing is effective
- Latex- or oil-based paint mixed with sand and applied to trees
- None registered
- Shotgun – 12- and 20-gauge
- Rifle – .22- and .17-caliber rimfire
- Body-gripping traps – at least 8- x 8-inch opening recommended
- Foothold traps (minimum jaw spread of 6 inches; offset jaws) in drowning sets
- Cage traps – Hancock- and Bailey-style beaver traps
Damage Prevention and Control Methods
The benefits of beaver ponds are not covered in depth here, but they are numerous. Beavers create habitat for fish, waterfowl, furbearers, shorebirds, reptiles, and amphibians. In many areas, beavers are an important resource for fur and food.
When dam-building conflicts with the objectives of humans, the damage may outweigh the benefits of beavers. Losses in the US have been estimated at $3 to $5 million annually for timber losses; crop losses; and damage to roads, dwellings, and property.
Beavers do not hibernate and can be controlled any time the law allows. When beaver colonies are well established over a large and contiguous area, achieving control is difficult and costly. If beavers on adjacent land are not controlled, expect periodic reinvasions and continual problems, even if all beavers are removed from the property where management occurred.
Beavers extensively modify their habitat. Disturbance by humans has little impact on beavers. Destruction of dams and daily removal of dam-construction materials may cause beavers to move to another site. Such activities are labor-intensive and expensive. Eliminate food, trees, and woody vegetation that are adjacent to ideal habitat for beavers. It is usually only feasible to do such drastic landscape changes for large highway projects.
Flow pipes can provide sufficient relief from flooding in some circumstances. Consult ICWDM (http://icwdm.com) for literature on flow pipes. Flow pipes are popular because beavers do not have to be killed. Installation of flow pipes, however, may result in the beavers simply moving up or down stream. Install flow pipes only when:
- landowners tolerate damage to trees or other plant life,
- water depth is sufficient to allow activity of beavers under ice (4 feet minimum),
- the area has sufficient room to handle typical spring flooding, and
- standing water will not undermine roads or septic systems.
It often is cost-prohibitive to exclude beavers from ponds, lakes, or impoundments. Protect valuable trees near waterways by encircling them with hardware cloth, woven wire, or other metal (Figure 6).
Construction of concrete spillways or other permanent structures may reduce the impact of beavers. A variety of techniques are available to protect culverts from obstruction by beaver dams, including fences. Consult the resources at ICWDM (http://icwdm.org) for details on constructing and maintaining these devices.
Figure 6. This fence would have worked had it been installed
before beavers damaged the tree.
Photo by Stephen M. Vantassel.
No frightening devices are effective for the control of beavers.
No chemical repellents are registered for management of beavers. Some trees may be protected by applying a mixture of 8 ounces of fine sand (30 mil, 70 mil, or mason sand) to 1
quart of oil or latex paint. Protect tree bark from the ground to a height of 4 feet. Stir the mixture frequently to keep the sand in solution. The color of the paint is a personal preference. Avoid painting young trees less than 6 feet tall. Opinions on the efficacy of this technique are mixed.
No toxicants are registered for the control of beavers.
Check with local and state regulations before shooting beavers. Ensure that safe shooting zones are available at the site. Notify local law enforcement personnel before initiating any shooting.
Beavers are most active from late afternoon to shortly after daybreak, depending on the time of year. They usually stay in a lodge or den during the day. One particularly effective method of attracting beavers is the removal of material from the dam. The sound of rushing water, and lower water level, will quickly attract beavers to repair the damage. Some states require permits to breach a beaver dam.
Shooting is most effective at night with spotlights. If shooting at night is not permitted, early evening and morning hours will be most productive. Choice of firearm depends on the range and situation. Most shooting is done at night with a shotgun at close range (within 20 yards), but .22- and .17-caliber rimfires have been used. Avoid ricochets if you are shooting with a rifle. Use of center-fire rifles is not recommended due to the increased risk of ricochet. Shooting generally is not effective for eliminating all beavers in an area, although it can quickly reduce a population or remove the last remaining beavers after a colony has been trapped.
The use of traps often is the most effective, practical, and environmentally safe method of control. Several methods and types of traps are effective for beavers, depending on the situation. The effectiveness of any type of trap is dependent on the knowledge of the trapper and the ability to read beaver signs, recognize food preferences, and use of the proper trap and trap placement. An experienced trapper with a dozen traps generally can remove all the beavers behind a single dam in a week. More effort will be required in a large watershed with several colonies. Almost anyone with experience and some outdoor savvy can become an effective beaver trapper in a short time. Check traps daily.
Use a walking staff when wading in ponds to locate deep holes, runs, or trails. Use of a walking stick will prevent stepping into water over waders or hip boots in winter, and help locate venomous snakes in the summer. It is not uncommon to find runs and entrances to lodges or dens 2 to 3 feet below the rest of the bottom of the impoundment in older ponds and bottomland swamps where beavers are common.
The Conibear® No. 330 is an effective and easy-to-use trap for catching beaver (Figure 7). When properly set, conibear-style traps will kill the beaver that has been captured. They are equally effective in deep and shallow water. Additional useful equipment includes an axe, hatchet (or large cutting tool), hip boots or waders, wire, and wire cutters.
Some trappers use a device called “setting tongs,” while others use a piece of 3/8– or ½-inch nylon rope to set the powerful traps. The 2 safety hooks, 1 on each spring, must be handled carefully during placement of the trap. In all circumstances, use a safety tool (Figure 8) in addition to the safety hooks, when setting conibear-style traps.
Figure 8. One type of Conibear® safety.
Photo by Wildlife Control Supplies, LLC.
Remove the hooks when the trap is set and make sure to keep hands and feet away from the center of the trap. If the extra safety catch is used, remove it before the safety hooks to keep it from getting in the way of the movement of the safety hooks.
Conibear-style traps are best set on solid ground using dry hands. When the springs are depressed and the safety hooks are in place, the trap can be carried into the water for proper placement.
Use at least 2 strong stakes to anchor the trap. Stakes can be made from trees found near most ponds and around dams made by beavers. Additional stakes may be used between the arms of the springs to help hold the trap in place. Do not place stakes on the outside of the spring arms. Stakes help guide beaver into the trap and are useful for holding a dive stick at the water surface (Figure 9). If necessary, the chain and circle attached to 1 spring eye can be attached to another stake. In deep water sets, a chain with a wire should be tied to something at or above the surface so the trapper can retrieve the trap.
Beavers can be trapped in may sets, including dam sets, slide sets, lodge sets, den sets, run sets, under-log sets, dive sets, pole sets, under-ice sets, deep water sets, and drain pipe sets. Choice of set depends on the situation and capability of the trapper. Beavers swim both at the surface and at the bottom, depending on the habitat and water depth. Beavers establish runs or trails, much like cows in a pasture, which they use habitually.
To stimulate movement of beavers at night, tear a hole in a dam so water rushes from the pond. Beavers quickly respond to the sound of running water and flow of current. Timing is critical: in the morning, open a hole in the upper side of the dam that is 18 to 24 inches wide and 2 to 3 feet below the level of the water to move a substantial amount of water out of the pond before evening. Set traps in front of the opening of the dam late that same evening.
Figure 9. Top – Conibear® in a beaver run. Bottom – Conibear®
used in a bait or castor mound set.
Image by Bob Noonan.
Two problems may arise if you set a trap in the morning as soon as a hole is made:
- the trap may be out of the water by evening when beaver become active, or
- a stick, branch, or other debris in the moving water may trip the trap.
The best dam sets are made 12 to 18 inches in front of the dam. Use stakes or debris on either side of the trap springs to create a funnel to make the beaver go into the jaws of the trap. Always set the trigger on a conibear-style trap in the first notch to prevent debris from tripping it before a beaver swims into the trap. The 2 heavy-gauge wire trigger wires can be bent outward, and the trigger can be set away from the middle to keep debris or non-target animals from tripping the trap.
Double-spring foothold traps are very effective when used properly. Use at least No. 3 double long-spring, coil spring, or traps of equivalent spread and strength (Figure 10). Use a drowning-set attachment with all foothold traps for beaver.
Figure 10. Number 4 double-long spring trap.
Photo by Dallas Virchow.
As a trap is tripped, the beaver will head for the water. Use a weight to hold the beaver underwater so it drowns. Some trappers stake the wire in deep water to accomplish drowning. If drowning sets are not used, beavers likely will escape and become trap-shy.
Placement is more critical with foothold traps than with conibear-style traps. Place foothold traps just at the edge of the water, slightly underwater, with the pan, jaws, and springs covered with leaves or debris, or pressed gently into the bottom of the pond in soft mud. Make a cavity under the pan so when the foot of a beaver hits the pan it will trigger the trap and allow the jaws to close. Place traps off-center of the trail or run to prevent “belly pinching,” or missing the foot or leg. With some experience, trappers learn to make sets that catch beavers by a hind leg rather than a front leg. The front leg is much smaller and easier to pull out of the trap. Make 2 sets in a slide, run, dam, and feeding site to increase success.
In some situations, combining methods can shorten the time necessary for trapping and increase success. Trappers have devised unique methods of making drowning sets. One simple and practical set is a slide wire with a heavy weight attached to 1 end, or with an end staked to the bottom in 3 or more feet of water (Fig. 11).
The other end of the wire is threaded through a hole in 1 end of a small piece of angle iron.
Figure 11. Diagram of a traditional drowning set. Note that a food lure with shaved branches can be used instead of castor. Image by Bob Noonan.
The chain of the trap is attached to a hole in the other end of the angle. The end of the wire is then attached to a tree or stake driven into the bank. When a beaver gets a foot or leg trapped, it immediately dives back into the water. As the angle slides down the wire, it prevents the beaver from reaching the surface. The angle iron piece will not slide up the wire and most often bends the wire as the beaver struggles, preventing the beaver from coming up for air. Trappers should be prepared to euthanize a beaver quickly that has been caught in a trap and has not drowned.
Foothold traps set near lodges or dens also are effective, especially for trapping young beavers. Place the set on the edge of the hole where the beaver first turns upward to enter the lodge or den, or place it near the bottom of the hole used for diving. Keep the jaws and pan off of the bottom by pulling the springs backward so a foot of a beaver that is swimming will trip the pan. Stake the set close to the bottom, or wire the trap to a log or root on the bottom, to avoid the need for drowning weights, wires, and angle iron pieces. Generally, more time and expertise is necessary to make effective sets with footholds than Conibears®.
Use scent or freshly cut limbs of cottonwood, aspen, willow, or sweetgum to entice beavers to foothold trap sets. Bait or scent is especially useful around scent mounds and near slides along banks or dams. Most trappers who use conibear-style traps do not employ bait or scent, although they occasionally are helpful. In some states, it is illegal to use bait or scent.
Several cage traps can be used to trap beavers. The most common are the Hancock-style trap and the Bailey Beaver Live Trap. Cage traps are heavy, expensive, and effective. To reduce theft, chain and/or place the traps in hard-to-reach areas.
The Hancock (Figure 12) uses strong springs to lift the beaver out of the water. Only 1 side of the trap moves, so the opposite side must be properly anchored to prevent the trap from flipping. Hancocks can be anchored to trees or set in deep water by driving 2 poles (3 inches wide and 5 feet in length) 24 inches apart and attaching the trap to the poles. In all circumstances, the trigger should be 3 to 4 inches below the surface of the water. Secure bait (shaved sticks with food or a gland lure) to the portion of the trap that is upright, 3 to 4 inches above the water line. Hancocks use powerful springs that are prone to accidental firing. People have been knocked unconscious when struck by a trap that has been triggered.
Figure 12. Demonstration set of a Hancock-style trap. The sticks are for bait. Photo by Stephen M. Vantassel.
Bailey traps (Figure 13) lay flat. Both sides of the trap move to envelope the beaver like a clamshell. The trap is prone to misfires when used incorrectly.
To remove beavers from Hancock and Bailey traps,slide a catch pole between the jaws, slipping the loop over the base of the tail and tighten. Use the catch pole to control the movements of the beaver. Open the cage and remove the animal. Beavers typically try to crawl away, though sometimes they turn and approach you. Direct the beaver into an open cage. Close the door while releasing the loop and removing the pole.
Figure 13. Bailey trap set to catch a beaver that approaches the tree. Photo by Stephen M. Vantassel.
Cable-restraints are a cost effective method for capturing beavers. Equipment costs far less than other trap designs, and they are more convenient in many situations. In addition, beavers can be captured alive and released elsewhere. Several variations and sets can be used. Cable-restraints frequently are placed under logs, near dens, and next to castor mounds. Drowning sets can be made using underwater anchors, slide cables, and slide locks.
Placement of cable-restraints is similar to that of traps. Look for runways and signs that indicate where activities of the beavers are focused. Find a suitable anchor such as a large tree, log, or root within 10 feet of the runway where the cable-restraint will be set. If necessary, anchor cable-restraints by rods driven into the ground, but this is more time consuming and less secure. Attach 3, 14-gauge wires to the anchor so that each can swivel freely. Cut each wire to length so they reach about 1 foot past the runway. Twist the wires together to form a strong braided anchor cable. Drive a stake into the ground near the runway and wrap the free end of the anchor cable around it twice (Figure 14).
Figure 14. Diagram of a cable-restraint set with bait.
Image by Bob Noonan.
Prepare a new, dyed, No. 4 beaver or coyote restraint consisting of 42 inches of 3/32-inch steel cable with an attached wire swivel and slide lock. Twist the free ends of the 3 anchor wires around the wire swivel on the end of the cable. Wrap the longest anchor wire around the base of the swivel and crimp it onto the cable about 2 inches from the swivel. Use both the stake and the supporting anchor wire to suspend a full-sized loop about 4 inches above the runway. If necessary, use sticks or other debris to guide beaver into the snare.
In freezing conditions, under-ice sets may be preferred. Both baited and unbaited sets can be very effective. Under-ice sets are intended to drown beavers as the ice refreezes after the set is constructed. In both cases, the set is composed of dry poles (2- to 3-inch diameter) placed into the bottom through holes that have been cut in the ice. The poles are lined with 2- to 10-inch loops of cable. Use ½-inch green poplar, aspen, or other branches as bait. In an un-baited set, 1 or more poles are placed in the channel to intersect and entangle the beaver as it passes. Routes that are habitually used by beavers are easy to identify after ice has formed, as bubbles are released from the fur of the beavers as they swim. Trails of bubbles can be seen in clear ice and are valuable in guiding placement of restraints.
Restraints should be checked at least every 24 hours. Use a catch pole or net to remove beavers that have been captured. Place animals in a cage for transfer, or use cable-restraints in kill sets.To reduce the risk of capturing non-targets, use restraints only in water. Check with the local wildlife agency for regulations, as cable-restraints are illegal in some states.
Handling – Relocation
Relocation is only feasible for rescues.
Translocation should only be used when recommended by your state wildlife agency.
Carbon-dioxide chambers are effective for euthanizing beavers. A single bullet to the brain is effective as well, but must be done carefully, as low-powered bullets may ricochet off the skull.
Consult your state regulations regarding disposal of carcasses.
Other Control Methods
Electronic wires and fertility (reproductive) control have been tried, but no other methods are practical for control of beavers.
Adapted and updated from a chapter by James E. Miller and Greg K. Yarrow in the book, Prevention and Control of Wildlife Damage, 1994, published by the University of Nebraska–Lincoln Extension.
- Tim L. Hiller, Oregon Department of Fish and Wildlife
- James Fitzpatrick, Rob Beckman, private animal handlers
- Lynn Braband, Cornell University