Monday, January 21, 2008

Busy Beavers

Beaver dams create deep diving pools that are inconvenient for their predators. Here's the new beaver dam on the creek, and a close-up of a slender branch they lopped and stripped with their teeth. The bark was food; the stick is building material. Back in '01 on a moonlit night a friend and I crept down to the creek and watched a beaver clan at work.

It sounds like: Crunch crunch crunch crunch, Ker-PLOOP! (that's one of the beavers diving into the creek). He or she then swims silently, along with the current, head above the water, nosing along a branch, either stripped or with bark. He or she gets it to the dam area, and the engineer beavers take over from there.

The last beaver dam here was built in 2001; it was three times this size, strong enough to walk across the creek on, and so tightly built a branch could hardly be pulled from it. The beavers of '01 felled trees a foot in diameter (crunch crunch crunch) and permanently changed the course of the creek. A torrential flash-flood destroyed their dam and they moved on, and there haven't been any more until this year. They work mostly with slender new trees, so this dam isn't quite as spectacular. A conservation guy told me not to worry about the fallen trees, because if beavers chewed them down, that was nature.

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