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 6 abandoned beaver dam DHJanzen100879.jpg high resolution
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The beaver dam that created the pond in image DHJanzen100878.jpg above - here supporting a herd of unruly students - shows clearly that the pond is abandoned. The water level is nearly a foot below the top of the dam, and the dam top is covered with herbaceous plants. While not visible, indeed, the water that used to pour over the top of the dam in many small places (the norm for an occupied dam) has cut a channel through the dam and every day cuts deeper into it, allowing the pond to escape. Were there a beaver colony present, they would have long before plugged the channel, raising the pond level to where it leaks over the top of the dam in many places. Beaver are fanatics about plugging running water. One standard method of trapping beaver is to make a small cut in the top of the dam. As soon as a beaver swimming in the pond hears the sound of that water running through the top of the dam, it goes to it to plug it and may then step in a trap placed at the cut. However, this is not an efficient way to trap (see below for other methods) because the beaver often arrives with an armful of mud and sticks to shove into the cut and sets off the trap with this material. Anyone who has had a pet beaver living at home has stories to tell about this instinct. One of the more common ones is that when a bathtub is being filled, a free ranging beaver will collect sheets off a bed to stuff into the bathtub to attempt to stop the flowing water. |
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