Beaver, Castor canadensis, damage management and control information
None are registered.
Trapping
The use of traps in most situations where beavers are causing damage is the most effective, practical, and environmentally safe method of control. The effectiveness of any type of trap for beaver control is dependent on the trapper’s knowledge of beaver habits, food preferences, ability to read beaver signs, use of the proper trap, and trap placement. A good trapper with a dozen traps can generally trap all the beavers in a given pond (behind one dam) in a week of trap nights. Obviously in a large watershed with several colonies, more trapping effort will be required. Most anyone with trapping experience and some outdoor “savvy” can become an effective beaver trapper in a short time. In an area where beavers are common and have not been exposed to trapping, anyone experienced in trapping can expect good success. Additional expertise and improved techniques will be gained through experience.
A variety of trapping methods and types of traps are effective for beavers, depending on the situation. Fish and wildlife agency regulations vary from state to state. Some types of traps and trapping methods, although effective and legal in some states, may be prohibited by law in other states. Individual state regulations must be reviewed annually before beginning a trapping program.
 
 
In some states where beavers have become serious economic pests, special regulations and exemptions have been passed to allow for increased control efforts. For example, some states allow trapping and snaring of beavers and other control measures throughout the year. Others, however, prohibit trapping except during established fur trapping seasons. Some states allow exemptions for removal of beavers only on lands owned or controlled by persons who are suffering losses. In some states a special permit is required from the state fish and wildlife agency.
Of the variety of traps commonly allowed for use in beaver control, the Conibear® type, No. 330, is one of the most effective (Fig. 8). Not all trappers will agree that this type of trap is the most effective; however, it is the type most commonly used by professional trappers and others who are principally trapping beavers. This trap kills beavers almost instantly. When properly set, the trap also prevents any escape by a beaver, regardless of its size. Designed primarily for water use, it is equally effective in deep and shallow water. Only one trap per site is generally necessary, thus reducing the need for extra traps. The trap exerts tremendous pressure and impact when tripped. Appropriate care must be exercised when setting and placing
 
the trap. Care should also be taken when using the Conibear® type traps in urban and rural areas where pets (especially dogs) roam free. Use trap sets where the trap is placed completely underwater.
Some additional equipment will be useful: an axe, hatchet, or large cutting tool; hip boots or waders; wire; and wire cutters. With the Conibear®-type trap, some individuals use a device or tool called “setting tongs.” Others use a piece of 3/8- or 1/2-inch (9- or 13mm) nylon rope. Most individuals who are experienced with these traps use only their hands. Regardless of the techniques used to set the trap, care should be exercised.
Earlier models of the Conibear® type of trap came with round, heavy steel coils which were dangerous to handle unless properly used in setting the trap. They are not necessary to safely set the trap. However, the two safety hooks, one on each spring, must be carefully handled as each spring is depressed, as well as during trap placement. On newer models an additional safety catch (not attached to the springs) is included for extra precaution against inadvertent spring release. The last step before leaving a set trap is to lift the safety hook attached to each spring and slide the safety hook back from the trap toward the spring eye, making sure to keep hands and feet safely away from the center of the trap. If the extra (unattached) safety catch is used, it should be removed before the safety hooks that are attached to the springs to keep it from getting in the way of the movement of the safety hooks.
Conibear®-type traps are best set while on solid ground with dry hands. Once the springs are depressed and the safety hooks in place, the trap or traps can be carried into the water for proper placement. Stakes are needed to anchor the trap down. In most beaver ponds and around beaver dams, plenty of suitable stakes can be found. At least two strong stakes, preferably straight and without forks or snags, should be chosen to place through each spring eye (Fig. 8). Additional stakes may be useful to put between the spring arms and help hold the trap in place. Do not place stakes on the outside of spring arms. Aside from serving to hold the trap in place, these stakes also help to guide the beaver into the trap. Where needed, they are also useful in holding a dive stick at or just beneath the water surface (Fig. 9). If necessary, the chain and circle attached to one spring eye can be attached to another stake. In deep water sets, a chain with an attached wire should be tied to something at or above the surface so the trapper can retrieve the trap. Otherwise the trap may be lost.
Trap Sets. There are many sets that can be made with a Conibear®-type trap (for example, dam sets, slide sets, lodge sets, bank den sets, “run”/trail sets, under log/dive sets, pole sets, under ice sets, deep water sets, drain  pipe sets), depending on the trapper’s capability and ingenuity. In many beaver ponds, however, most beavers can be trapped using dam sets, lodge or bank den sets, sets in “runs”/trails, dive sets or sets in slides entering the water from places where beavers are feeding. Beavers swim both at the surface or along the bottom of ponds, depending on the habitat and water depth. Beavers also establish runs or trails which they habitually use in traveling from lodge or den to the dam or to feeding  areas, much like cow trails in a pasture.
Place traps directly across these runs, staked to the bottom (Fig. 10).
Use a good stake or “walking staff’ when wading in a beaver pond to locate deep holes, runs, or trails.
This will prevent stepping off over waders or hip boots in winter, and will help ward off cottonmouth snakes in the summer. The staff can also help locate good dive holes under logs as you walk out runs or trails. In older beaver ponds, particularly in bottomland swamps, it is not uncommon to find runs and lodge or bank den entrances where the run or hole is 2 to 3 feet (0.6 to 0.9 m) below the rest of the impoundment bottom.
To stimulate nighttime beaver movement, tear a hole in a beaver dam and get the water moving out of a pond. Beavers quickly respond to the sound of running water as well as to the current flow. Timing is also important if you plan to make dam sets. Open a hole in the dam about 18 inches to 2 feet (46 to 60 cm) wide and 2 to 3 feet (60 to 90 cm) below the water level on the upper side of the dam in the morning. This will usually move a substantial amount of water out of the pond before evening (Fig. 11). Set traps in front of the dam opening late that same evening. Two problems can arise if you set a trap in the morning as soon as a hole is made: (1) by late evening, when the beavers become active, the trap may be out of the water and ineffective; or (2) a stick, branch, or other debris in the moving water may trip the trap, again rendering it ineffective.
The best dam sets are made about 12 to 18 inches (30.8 to 45.7 cm) in front of the dam itself. Using stakes or debris on either side of the trap springs, create a funnel to make the beaver go into the jaws of the trap. Always set the trigger on the Conibear®-type trap in the first notch to prevent debris from tripping it before the beaver swims into the trap. The two heavy-gauge wire trippers can be bent outward and the trigger can be set away from the middle if necessary, to keep debris from tripping the trap. This can also keep small beaver or possibly fish or turtles from springing the trap.
Double-spring leghold traps have been used for hundreds of years and are still very effective when properly used by skilled trappers. Use at least No. 3 double (long) spring or coil spring type leghold traps or traps of equivalent size jaw spread and strength. Use a drowning set attachment with any leghold trap (Fig. 12). As the traps are tripped, the beaver will head for the water. A weight is used to hold the trapped beaver underwater so that it ultimately drowns. Some trappers stake the wire in deep water to accomplish drowning. If leghold traps are not used in a manner to accomplish drowning, there is a good likelihood that legs or toes will be twisted off or pulled loose, leaving an escaped, trap-wise beaver.
Placement is even more critical with leghold traps than with the Conibear®-type. Place leghold traps just at the water’s edge, slightly underwater, with the pan, jaws, and springs covered lightly with leaves or debris or pressed gently into the pond bottom in soft mud. Make sure there is a cavity under the pan so that when the beaver’s foot hits the pan, it will trigger the trap and allow the jaws to snap closed. Place traps off-center of the trail or run to prevent “belly pinching” or missing the foot or leg. With some experience, beaver 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 twist off or pull out.
Sometimes it’s wise, when using leghold traps, to make two sets in a slide, run, dam, or feeding place to increase trapping success and remove beavers more quickly. In some situations, a combination of trapping methods can shorten trapping time and increase success.
Trappers have come up with unique methods of making drown sets. One of the simplest and most practical is a slide wire with a heavy weight attached to one end, or with an end staked to the bottom in 3 or more feet (>0.9 m) of water. The other end of the wire is threaded through a hole in one end of a small piece of angle iron. The trap chain 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 (Fig. 13). When the beaver gets a foot or leg in the trap, 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 back up the wire and most often bends the wire as the beaver struggles, thus preventing the beaver from coming up for air. Trappers should be prepared to quickly and humanely dispatch a beaver that is caught in a trap and has not drowned.
The leghold trap set in lodges or bank dens is also 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 dive hole. Keep the jaws and pan off of the bottom by pulling the springs backward so that a swimming foot 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 leghold traps and snares than is required with the Conibear®-type trap.
Use scent or freshly cut cottonwood, aspen, willow, or sweetgum limbs to entice beaver to leghold trap sets. Bait or scent is especially useful around scent mounds and up slides along the banks or dams. Most trappers who use Conibear®-type traps do not employ baits or scent, although they are occasionally helpful. In some states it is illegal to use bait or scent.
Several other types of traps can be used, including basket/suitcase type live traps. These are rarely used, however, except by professionals in urban areas where anti-trap sentiment or other reasons prevent the killing of beavers. These traps are difficult and cumbersome to use, and will not be further discussed here for use in beaver damage control. Any type of traps used for beavers or other animals should be checked daily.
Snaring can be a very cost-effective method for capturing beavers. Snaring equipment costs far less than trapping equipment and is more convenient to use in many situations. In addition, beavers can be captured alive by snaring and released elsewhere if desired.
Snare placement is similar to trap placement. First, look for runways and fresh sign that indicate where beaver activities are focused. Find a suitable anchor such as a large tree, log, or root within 10 feet (3 m) of the runway where the snare will be set. If necessary, anchor snares by rods driven into the ground, but this is more time consuming and less secure. Attach three 14-gauge wires to the anchor so that each can swivel freely. Cut each wire to length so they reach about 1 foot (30 cm) past the runway. Twist the wires together to form a strong braided anchor cable. Drive a supporting stake into the ground near the runway and wrap the free end of the anchor cable around it twice. Prepare a new, dyed, No. 4 beaver or coyote snare, consisting of 42 inches (107 cm) of 3/32-inch (2.4-mm) steel cable with an attached wire swivel and slide lock. Twist the free ends of the three anchor wires around the wire swivel on the end of  the snare cable. Wrap the longest anchor wire around the base of the wire swivel and crimp it onto the snare cable about 2 inches (5 cm) from the swivel. Use both the stake and the supporting anchor wire to suspend a full-sized loop about 4 inches (10 cm) above the runway. If necessary, use guide sticks or other natural debris to guide beaver into the snare.
The described snare set is very common, but there are several variations and sets that can be used. Snares are frequently placed under logs, near bank dens, and next to castor mounds. Drowning sets can be made using underwater anchors, slide cables, and slide locks.
Snares should be checked at least every 24 hours. Dispatch snared beavers with a sharp blow or shot to the head. Beavers can be chemically immobilized and transported to suitable sites for release if desired.
Snares must be used with great care to avoid capturing nontarget animals. Avoid trails or areas that are used by livestock, deer, or dogs. Check with your local wildlife agency for regulations associated with trapping and snaring. Snaring is not allowed in some states.
For more information about the use of snares see  A Guide to Using Snares for Beaver Capture  (Weaver et al. 1985) listed at the end of this chapter.
Fig. 14. Conibear® in culvert set. When beavers are stopping up a drainage culvert, (1) clean out the pipe to get water flowing through freely; (2) set the trap at the level of the drain pipe entrance, but far enough away to clear the culvert when the beaver enters; (3) put stakes on either side to make the beaver enter the trap correctly.
Shooting
In some states, because of the extent of  damage caused by beavers, regulations have been relaxed to allow shooting. Some  states even allow the use of a light at night to spot beavers while shooting.  Before attempting to shoot beavers, check regulations, and if applicable, secure  permits and notify local law enforcement personnel of your intentions. Beavers  are most active from late afternoon to shortly after daybreak, depending on the  time of year. They usually retire to a lodge or bank den for the day. Therefore,  if night shooting is not permitted, the early evening and early morning hours  are most productive. Choice of weapons depends on the range and situation. Most  shooting is done with a shotgun at close range at night. Shooting alone is  generally not effective in eliminating all beaver damage in an area. It can,  however, be used to quickly reduce a population.
Other Methods
Because of the frustration and damage  beavers have caused landowners, almost every control method imaginable has been  tried. These range from dynamiting lodges during midday to using snag-type fish  hooks in front of dams, road culverts, and drain pipes. Such methods rarely  solve a damage problem, although they may kill a few beavers and nontarget  species. They are not recommended by responsible wildlife professionals. One  method used occasionally along streams prone to flooding is shooting beavers  that have been flooded out of lodges and bank dens. This method is often  dangerous and rarely solves a damage problem.
Economics of Damage and Control
The economics of beaver damage is somewhat dependent on the extent of the damage before it has been discovered. Some beaver damage problems are  intensive, such as damage  The most important point is that damage control should begin as soon as it is evident that a beaver problem exists or appears likely to develop. Once beaver colonies become well established over a large contiguous area, achieving control is difficult and costly. One of the most difficult situations arises when an adjacent landowner will not allow the control of beavers on their property. In this situation, one can expect periodic reinvasions of beavers and continual problems with beaver damage, even if all beavers are removed from the property where control is practiced.
Although benefits of beavers and beaver ponds are not covered in depth here, there are a number. Aside from creating fish, waterfowl, furbearer, shorebird, reptile, and amphibian habitat, the beaver in many areas is an important fur resource, as well as a food resource. For those who have not yet tried it, beaver meat is excellent table fare if properly prepared, and it can be used whether the pelts are worth skinning or not. It also makes good bait for trapping large predators.
Proper precautions, such as wearing rubber gloves, should be taken when skinning or eviscerating beaver carcasses, to avoid contracting transmissible diseases such as tuleremia.
Acknowledgments
The authors thank, for their cooperation, past and present employees of the Fish and Wildlife Service, US Department of the Interior, county extension agents with the Cooperative Extension Service in various states, cooperators with the USDA-APHIS-ADC program in a number of states, and the many landowners with beaver problems across the South. The experience gained in efforts to assist landowners with wildlife damage problems provided most of the information contained herein.
Figures 1, 2, 4 and 5 from Schwartz and Schwartz (1981).
Figure 3 by Jill Sack Johnson.
Figure 6 and 7 by the authors.
Figures 8 through 12 and 14 from Miller (1978).
Figure 13 by Jill Sack Johnson after Miller (1978).
For Additional Information
Arner, D. H., and J. S. Dubose. 1982. The impact of the beaver on the environment and economics in Southeastern United States. Trans. Int. Congr. Game Biol. 14:241-247.
Byford, J. L. 1976. Beavers in Tennessee: control, utilization and management. Tennessee Coop. Ext. Serv., Knoxville. Pub. 687. 15 pp.
Dyer, J. M., and C. E. Rowell. 1985. An investigation of techniques used to discourage rebuilding of beaver dams demolished by explosives. Proc. Eastern Wildl. Damage Control Conf. 2:97-102.
Hicks, J. T. 1978. Methods of beaver control. Final Rep., Res. Proj. No. W-37-R, Georgia Game Fish Div., Dep. Nat. Res. 3 pp.
Hill, E. H. 1974. Trapping beaver and processing their fur. Alabama Coop. Wildl. Res. Unit, Agric. Exp. Stn., Auburn Univ. Pub. No. 1. 10 pp.
Miller, J. E. 1972. Muskrat and beaver control. Proc. Nat. Ext. Wildl. Workshop, 1:35-37.
Miller, J. E. 1978. Beaver — friend or foe. Arkansas Coop. Ext. Serv., Little Rock. Cir. 539. 15 pp.
Roblee, K. J. 1983. A wire mesh culvert for use in controlling water levels at nuisance beaver sites. Proc. Eastern Wildl. Damage Control Conf. 1:167-168.
Roblee, K. J. 1987.The use of the T-culvert guard to protect road culverts from plugging damage by beavers. Proc. Eastern Wildl. Damage Control Conf. 3:25-33
Schwartz, C. W., and E. R. Schwartz. 1981. The wild mammals of Missouri, Rev. ed. Univ. Missouri Press, Columbia. 356 pp.
von Oettingen, S.L. 1982. A survey of beaver in central Massachusetts for  Giardia lamblia. M.S. Thesis, Univ. Massachusetts, Amherst. 58 pp.
Weaver, K. M., D. H. Arner, C. Mason, and J. J. Hartley. 1985. A guide to using snares for beaver capture. South. J. Appl. For. 9(3):141-146.
Wood, G. W., and L. A. Woodward. 1992. The Clemson beaver pond leveler. Proc. Annu. Conf. Southeast Fish Wildl. Agencies.
Editors