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Mountain Beavers | Mountain Beaver Overview | Mountain Beaver Damage Assessment | Mountain Beaver Damage Management | Mountain Beaver Resources | Mountain Beaver Acknowledgments | ICWDM | Wildlife Species Information |
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Mountain Beavers
Mountain beavers cause serious economic loss by burrowing through and feeding on garden vegetables, berry plants, and young trees. They use drainage ditches for burrow sites, and their burrows may undermine road-ways.
Mountain beavers are a major factor limiting reforestation in the Pacific Northwest (Borrecco and Anderson 1980, Evans 1987a). Plantations are most susceptible to damage for 4 years after planting and when pre-commercially thinned at about 12 to 15 years (Evans 1987a). Mountain beavers clip seedlings and gnaw saplings and the stems and bark of larger trees.
Mountain beavers normally clip seed-lings through at a 45o angle. On small seedlings this clipping may be difficult to distinguish from rabbit damage; however, rabbits seldom clip stems larger than 1/4 inch (0.6 cm) in diameter or 20 inches (50 cm) above ground level, whereas mountain beavers often cut stems larger than 1/2 inch (1.3 cm) in diameter and up to 9 feet (3 m) above ground (Lawrence et al. 1961). Mountain beavers leave branch stubs, cut at a 45o angle, protruding from the main stem. The bark of the main stem shows horizontal tooth marks and vertical claw marks (Packham 1970). Run-ways and burrows are present in or near the damaged area.
Summary of Damage Prevention and Control Methods
Exclusion
Use plastic mesh seedling protectors on small tree seedlings. Wire mesh cages are somewhat effective, but large diameter cages are expensive and allow animals to enter them.
Exclusion from large areas with buried fencing is impractical for most sites.
Cultural Methods/Habitat Modification
Plant large tree seedlings that will tolerate minor damage.
Burn or remove slash to reduce cover.
Tractor scarification of sites will destroy burrow systems.
Remove underground nests to reduce reinvasion.
Frightening
Not applicable.
Repellents
36% Big Game Repellent Powder has been registered for mountain beaver in Washington and Oregon.
Toxicants
A pelleted strychnine alkaloid bait was registered in Oregon but may be discontinued.
Fumigants
None are registered.
Trapping
No. 110 Conibear® traps placed in main burrows are effective but may take nontarget animals using burrows, including predators. Welded-wire, double-door live traps are effective and selective, but are primarily useful for research studies and removal of animals in urban/ residential situations.
Shooting
Not applicable.
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Mountain Beavers | Mountain Beaver Overview | Mountain Beaver Damage Assessment | Mountain Beaver Damage Management | Mountain Beaver Resources | Mountain Beaver Acknowledgments | ICWDM | Wildlife Species Information |
