Biology Reference
In-Depth Information
Dynamite may then become the weapon of choice, but even blowing a beaver dam to hell and gone
won't work unless it's done so late in the year that the beavers have no chance to rebuild before winter.
Otherwise the dam is back in a trice, the beavers are again in business, and flooding remains a prob-
lem. If the dam is totally destroyed late in the year, however, the beavers are doomed to starve or fall to
predators as soon as winter arrives.
So-called “beaver cheaters”—long, perforated pipes or wood-and-screen structures inserted through
the dam—sometimes work. With their upstream ends near the bottom of the pond and far enough above
the dam, these devices are sometimes able to confuse the beavers and prevent them from discovering
the source of the leakage. At other times, though, the dam builders, with their uncanny ability to detect
current, will locate and plug the offending structures.
Another serious problem is that beavers fail to distinguish between fruit and shade trees and wild
trees. Homeowners are understandably upset when this happens, yet the beavers are often forced to
utilize every inch of available habitat—including cultivated trees and shrubs. This, of course, is small
solace to the person whose prize fruit trees or treasured shade trees suddenly resemble the aftermath of
George Washington's mythical “Father, I cannot tell a lie” episode.
A neighbor of mine described just such an incident. Several years ago he lived on the edge of a large,
marshy area. Beavers soon appropriated this spot and built a dam and lodge. There were several homes
bordering this new beaver pond, and for a time everyone was delighted by the new residents. Then the
problems began.
Each year the beavers raised the dam and the water level a bit, and after four or five years the water
began creeping into septic-system leach fields. Moreover, the beavers began to run out of food and
sought whatever they could find around their pond. What they could find happened to include the fruit
trees in this man's backyard. Formerly very pro-beaver, his opinion, he admitted, underwent a rapid and
dramatic shift at that point. “I like beavers,” he commented dryly, “but I think I like apple trees more.”
Unsuccessful efforts were made either to evict the beavers by peaceable means, or to lower the level
of their impoundment. The dam was torn out repeatedly, and was promptly restored by the beavers on
each occasion. Then supposedly beaverproof outlet structures were installed, but the clever and indus-
trious rodents managed to plug them all.
Finally an adjoining homeowner, whose septic system was seriously impaired by the beaver flowage,
obtained a permit from the state to kill the beavers. This caused a neighborhood squabble, with some
opposed to killing the beavers (mainly those who hadn't suffered beaver damage), and others in favor
of their summary execution (mainly those who
had
suffered damage).
In the midst of this turmoil, the beavers themselves solved the problem. Constantly seeking new
sources of food and building supplies, they began to cross a busy paved highway adjoining their pond.
Beavers weren't designed by nature for crossing highways safely, and humans in automobiles soon be-
came predators, albeit unintentionally, of these particular specimens.
