Beaver

Scientific name: Castor canadensis

Biology.
Adult body length (without tail): 25 to 30 inches
Adult body weight: 30 to 70 pounds
Gestation period: 128 days
Litters per year: 1
Litter size: 1 to 8 young (usually 3 to 4)
Breeding season: January to March
Birthing season: April to June
Age at which young are weaned: 6 weeks to 3 months
Activity period: Night, pre-sunset through post-dawn
Range: 1/2 to 2 square miles
Primary foods: Live bark, herbaceous and aquatic plants and crops

Pest status. Beavers are problematic to humans as a result of their behavioral tendency to gnaw and fell trees, build dams in water systems (e.g., streams and culverts) and damage (by gnawing) personal property items made of wood. Beaver dams have been responsible for water systems overflowing their banks and subsequent flooding of surrounding areas. The trees they girdle and fell include bottomland hardwood timber and ornamental trees valued in the millions of dollars.

CONTROL
Habitat Modification and Harassment. Continuing (often daily) efforts to destroy beaver dams and removal of their component materials is a painstaking measure that may eventually discourage beavers from rebuilding dams in a particular site.
Beaver pond leveler systems (e.g., Clemson-type), constructed of perforated PVC pipe sections wrapped with heavy-gauge wire mesh and connecting to non-perforated sections of PVC pipe, can be installed to allow sufficient water from upstream to bypass the beaver dam and flow beneath it in the deepest part of the channel.

Physical / Mechanical Control
Exclusion. Valuable ornamental trees can be protected from beavers by encircling the trunks with protective metal barriers or fences at least 36 inches high.

Live-trapping. Leg-hold traps (No. 3 or 4 double spring) work well if placed strategically and concealed on beaver trails along the bank and near water entry points (slides). Although leg-hold traps actually capture beavers alive, recommended trap anchoring methods, involving underwater staking or attachment to weighted slide wires that lead to deep water, generally result in the animals drowning. Leg-hold trap sets not rigged to drown captured beavers must be checked daily.
Snares, comprised of staked steel cable (3/32-inch diameter) terminating in a noose and slide-lock, can be placed in the same settings as leg-hold traps. Snares (No. 4) are suspended at head-height, in concealment along beaver trails. Beavers captured in snares remain alive; therefore, snare sets must be checked daily for humane reasons.

Lethal-trapping. Several types of lethal traps have proved to be effective for reducing beaver populations in problematic situations. Multiple traps (sets) should be anchored underwater (so as to reduce the risk of trapping dogs and other non-target animals) in high activity areas, such as near beaver lodge/den entrances and runs. Wire mesh suitcase-type traps, which encase and drown the captured animal, is a commonly-used and effective method to capture beavers.