When Beavers Become a Nuisance

by Dan Banks
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The beaver, Castor canadensis, is Canada's national emblem. The exploration and settlement of Canada by Europeans was largely a result of the search for beaver pelts.

These large, aquatic rodents usually live in colonies consisting of a single family unit. A typical colony consists of two adults, two to three yearlings, and three to four young of the year (kits). Two-year-olds leave or are driven from the colony before the birth of the kits in early spring.

Beavers prefer slow-moving streams with muddy bottoms, but are also found in fast, rocky bottom streams, and in lakes. Some colonies will excavate water level around the lodge, and to move in winter food supplies.

During summer months beavers eat mostly grasses and broadleaf plants, forbs, leaves, and other green vegetation. During the rest of the year their main food supply is the inner bark layer of assorted hardwood trees - especially aspen, willow, maple, and birch. Beaver become very active in early fall, cutting and storing large amounts of hardwood branches in underwater food piles called caches near their lodge for under-ice use later in the winter.

Beaver die in a number of ways. Coyote, bear, and bobcat may kill beaver they catch on land. Winter or spring floods may cause some beaver to drown or starve. Newly dispersed young, especially those in poor health, may die as a result of inadequate food caches.

Damage Identification

It's usually easy to identify a beaver colony - recently flooded forest or agricultural lands, fallen hardwood trees with pointed stumps and wood chips looking like they came from a giant chainsaw, roadside culverts mysteriously plugged overnight, or backside holes caused by burrowing.

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Prevention, Control & Precautions

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