Trappers Alley

Beaver Lodge In Ortonville,MI.

----BEAVER DAMAGE CONTROL----

--------BIOLOGY---------

The beaver is a semi-aquatic mammal and the largest native North American rodent. Mature males weigh 40 to 60 lb but can weigh over 100 lb. Only one litter of four to six kits is produced each year from April to June following a 100 to 105 day gestation. At two years, beaver leave the home colony to search for winter quarters which may take them up to 10 km away. The life span of beaver is 5 to 10 years with some living up to 20 years. Because of their size, behavior and habitat, beaver have few enemies. Mortality is highest during the first year; coyotes, wolves, bears and other large carnivores are the main predators. Apart from occasional sickness, trapping is the only major cause of death. Research shows that beaver can maintain or increase their numbers with an annual trapping rate of 30 to 40 per cent. It is no surprise then, that beaver numbers never seem to decline significantly in problem areas where removal is the major method of control. Beaver ponds play a valuable and significant role in the formation of Alberta's plant and animal communities. Their dams create ponds that contribute to the stabilization of water tables and help reduce rapid rain runoff. Dams also help reduce soil erosion and improve soil quality, since runoff deposits in quiet pools near beaver dams. As a result, beaver habitat is often rich in plant and animal life, making beaver ponds excellent sites for observing nature. Beaver ponds also provide recreation such as fishing and hunting and have great aesthetic value. Furthermore, beaver ponds create habitat for other fur bearing animals with good harvest value. Harvesting of beaver is a major source of income to Alberta's fur trade industry and annually represents about 30 per cent of gross fur sale revenues ($3.6 million in 1987). Giardiasis (inaccurately called "beaver fever") is a disease caused by a microscopic parasite found in the excrement of infected birds and mammals, including beaver. Beaver often get the blame for the spread of the disease because they are the most obvious carrier in water contaminated with the parasite.

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---DAMAGE----

Beaver problems occur wherever there are trees and water. Most conflicts with beaver, however, occur in the aspen parkland region which covers more than half the province's farm land. In these areas, beaver cause problems by flooding cultivated land, hay fields, pasture land, roadways, and often detour or restrict water flow in stream ways. Damage in urban areas is generally minor. However, beaver problems can be severe where beaver girdle or cut down valuable ornamental trees and shrubs or undermine yards, walks and roadways with their burrowing.

----BEAVER DAMAGE CONTROL----

Before beginning any beaver control action, assess the beaver problem fairly and objectively. Are beaver really causing damage or creating hardship requiring control action? Often the very presence of beaver is seen as a problem when in fact the beaver are causing no harm. You should also determine the type of damage or problem the animals are causing, then match the most appropriate and cost effective controls to the situation. Once you have decided to control beaver damage there are three control options to choose from: 1.prevention--treat the area to prevent or reduce the damage 2.live trap and relocate the problem beaver (3) destroy the problem beaver and remove the dam Since live trapping and relocating beaver is often cost prohibitive, its use is limited and often not practical. Also, research has shown this method of control to be of questionable value because translocated beaver either return to the problem area or seldom survive relocation. However, in urban areas where lethal trapping may be illegal or unsafe, live capture and translocating may be the only alternative.

<----PREVENTION----

Tree protection:

Beavers can be fenced out of a treed area or individual trees can be wrapped with galvanized metal or chicken wire to a height of at least 1 m. Valuable broad-leaved trees can be protected by a galvanized metal fence at least 1 m (3 ft) high and 0.5 m (18 in.) below ground, however, this method can be expensive.

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---REPELLANTS----

Thiram, the only repellent known to reduce beaver damage, is applied directly to trees and shrubs. However, it will usually work only where beaver have alternate sources of food, i.e. other trees that they can cut for food. No licence or permit is required to purchase or use this product. Water level control without beaver removal Where flooding is the major problem, the use of a "beaver drain pipe" is the best solution. Make a "beaver pipe" or water level stabilization device by fitting two plastic sewer pipes together and perforating one of them. The diameter of the pipes can be 4, 6,8, or 10 in., depending on volume of water in the stream. Dig a hole through the beaver dam in line with the original stream channel. Set three-quarters of the pipe at almost any level in the dam, extending the perforated end out into the pond (see figure 1).A weight should be placed on the end of the pipe. Allow about one quarter of the pipe to extend on the downstream side of the dam. Beaver pipes work best where the flooded area is more than one acre and the minimum water depth at the pond is 0.5 m (18 in.) or deeper. Figure 1. Drain Pipe:

In the case of a plugged culvert, the dam should be removed and a heavy wire mesh fence (No.6 concrete reinforcing wire) should be installed around the mouth of the culvert and secured with steel posts. When the beaver build a dam on the fence, a 11beaverpipe11 can be placed through the fence to keep the water at a desired level(see figure 2). Figure 2. Beaver Pipe:

A single "beaver pipe" can handle the normal runoff from a 2,000-acre drainage area; some installations use up to three pipes. It is not feasible to manage streams with flows from drainage areas exceeding 10 to 11 square km with "beaver pipes." A pipe installation usually provides a long-term water level control at a nuisance site. However, it can also provide control until beaver are removed from the site through a regular fur trapping season. Benefits of a pipe installation include elimination or reduction of beaver damage as well as the conservation of a beaver colony and a steady supply of stock water. In problem areas where emigrating beaver continually reoccupy the site, trapping would be necessary on a yearly basis. If trapping is required five or more years out of fifteen, a pipe installation is a more effective and less costly method of controlling the problem. Three important requirements need to be considered using beaver pipes: 1.water depth and area must be adequate to install pipes properly. 2.the normal flow of the stream during the control period must not exceed the flow capacity of the pipe. 3.you must accept short periods of high water levels.

----BEAVER GUARDS----

A wire mesh cylinder of 10 X 10 cm (4in.x4in.) welded wire mesh (0.4 gauge or 0.25 in. diameter) will protect culverts from beaver. The diameter of the cylinder should be the same as the culvert and may be in a horizontal or vertical position(see figure 3). The length of the cylinder may vary but as a general rule it should be twice its diameter. Secure the cylinder with heavy metal stakes and fasten it to the culvert. Figure 3. Beaver Guards:

----SHOOTING AND TRAPPING---- Shooting - Shooting beaver (where legal) can be an effective control technique. At dawn and dusk, keep hidden and patiently stalk or wait for beaver near their dams. Because beaver spend most of their time in water, the only target they offer is a partially submerged head. Skilled marksmanship is needed to shoot beaver. Practice shooting small targets the size of an oil can at distances of 50 to 100 yards. Trapping - Trapping in agricultural areas, beaver damage usually occurs when fur values are low and beaver numbers high. The solution is a combination of preventive control and timely beaver harvest. To do this, beaver numbers need to be regularly and continually monitored to observe population shifts and so avert potential problems. Contact your Agricultural service board or Fish and Wildlife officer for the name of a local trapper if you do not want to remove the beaver yourself. Figure 4. Conibear Trap and Setting Equipment:

You can resolve many beaver problems by trapping. The type of trap and set used depends on the type of problem, location and time of year. Beaver are generally easy to trap, however, they can quickly become "trap-wise" from poorly placed traps or inferior equipment.

----EQUIPMENT----

The most effective trap for beaver is the body-grip trap called a coni bear. The proper size of coni bear trap for beaver is 280 through 330. Set and handle coni bear traps with great care. To set them you will need a safety clamp and a seven foot nylon rope to ensure your own safety(see figure 4). You should also always carry a hacksaw blade with you. A hacksaw blade is your backup safety if you get caught in a trap and cannot escape. Most professional trappers sew a hacksaw blade into their trapping coat so they will always have a saw with them. Conibear traps are equipped with safety catches on each spring but the safety clamp should always be used when setting and placing them. The springs of the conibear trap can also be set with the nylon rope by tying the rope to one spring coil and running it through both coils two or three times. This will allow you to easily pull the spring coils together and secure them with the safety catches.

----CANAL SET----

One of the easiest and most successful coni bear trap sets is the canal set. Place a heavy pole through each spring coil of the trap. Use baling wire to attach this to two anchor stakes and drive the anchor stakes into the canal banks. When set, the pole should touch the water surface to cause the beaver to dive under it into the trap. Figure 5. Canal Set:

If the canal is wider than l6 to 18 in. place a short pole on either side of the trap to encourage the beaver to enter the trap. Note: Bend the trigger wires to the sides as shown in figure 5 so the approaching beaver does not sense the trap.

----BANK DEN SET----

Place the trap at the bank den entrance and put a stake through each spring coil. Drive the two stakes into the mud to secure this underwater set. The bank den set may also be used at the entrance to the beaver lodge. Figure 6. Bank Den Set:

----DAM SET----

Locate the travel path on top of the dam and set a coni bear trap as shown in figure 7. The trap may be camouflaged with grass, twigs or leaves, to break the trap outline. Scent lure may be placed on the trail about two ft. from the trap. Figure 7. Conibear Set at Dam:

----WATER EDGE SET----

Another set for unwary beaver is to secure a conibear trap in the water about 12 to 18 in. from bait or lure placed at the water1s edge. The trap should never be more than half submerged in the water. Use grass or leafy branches to camouflage the trap outline. Do not place camouflage material within the trap1s jaws.

----CUT TREES BY BEAVER----

----BEAVER DAM IN WINTER----

Clements, C. 1991. Beavers and Riparian Ecosystems. Rangelands 13(6).

D’Eon, R.G. et al. 1995. The Beaver Handbook: A Guide to Understanding and Coping with Beaver Activity. Northeast Science & Technology.

Hammerson, G. 1994. Beaver (Castor canadensis): Ecosystem Alterations, Management, and Monitoring. Natural Areas Journal 14(1):44-57.

Maret, J.M., Parker, and Fanny, T., 1987. The Effect of Beaver Ponds on the Nonpoint Source Quality of a Stream in Southwestern Wyoming. Water Resources 21(3): 263-268.

Medin, D., and W. Cleary, 1990. Bird Populations in and Adjacent to a Beaver Pond Ecosystem and Adjacent Riparian Habitat in Idaho. Inter- mountain Forest and Range Experiment Station. USDA Forest Service. Ogden, UT.

Naiman, R., J. Melello and J. Hobbie. 1986. Eco- system Alteration of Boreal Forest Streams by Beaver. (Castor canadensis). Ecology 67: 1254- 1269.

Olson, R., and W.A. Hubert. 1994. Beaver: Water Resources and Riparian Habitat Manager. University of Wyoming. Laramie, WY. 48 pp.

Rue, L. 1981. Furbearing Animals of North America. Crown Publishers. New York, NY. 336 pp.

Smith, B. et al. 1991. Modification of Stream Ecosystem Structure and Function by Beaver. Canadian Journal of Zoology 69:55-61.

Contacts

Information about Clemson Pond Leveler: Dr. Gene Wood. Clemson University. (803) 656-3117.

To obtain a copy of The Beaver Handbook write: Ontario Ministry of Natural Resources. Northeast Science and Technology Center. 60 Wilson Ave. Timmins, Ontario P4N 2S7.

----BEAVER RANGE----