The Beavers Are Back

Outflow pipe of retention pond backed up by beavers, with chewed log propped up (Centennial Woods)

Back in 2012, a pair of beavers moved into the retention pond in Centennial Woods sometime in the September. Once we discovered them, my fall UVM course, Natural History of Centennial Woods, studied the history of beavers in CW and their impact on natural (and unnatural) areas. While working on a mapping project, one of my students discovered that another pair of beavers had abandoned the retention pond by the Sheraton (just after it had been cleared of trees around the entire perimeter). Sure enough, the next day there were 4 beavers in the retention pond by Centennial Field! Sometime later another faculty member alerted me to the fact that UVM had set kill traps to remove all the beavers – apparently the water level in the pond needs to be below a certain level and the damming beavers had raised the water above that level. After many emails and an article in 7-Days, UVM finally decided to pull the traps. I had maintained that the beavers would move on in the spring because the pond isn’t great habitat, which ultimately proved true. To prevent further colonization by beavers, UVM set beaver guards around some of the hardwoods that surrounded the pond, and shored up the fencing by patching up the chain link fence, though most of this seemed to be more for appearances.

Caging around red maple to prevent beavers from colonizing the retention pond.

None of this has worked and beavers have been in and out of the pond over the past 5 years, beaver baffles are pretty much the only effective long-term preventative solution other than clearcutting. The beavers prior to this fall have been itinerant, never staying long enough to build a lodge or dam up the outflow. This highlights just how marginal the habitat around the pond is for beavers (lots of Phragmites, staghorn sumac, glossy buckthorn, hemlock, pine, and other things not high on the list of a beaver’s preferences).

Retention Pond in Centennial Woods dammed up by beavers

I only noticed that the pond seemed to be higher than usual a few weeks ago, suggesting that beavers had moved back in and plugged up the outflow, flooding the pond. A quick survey yesterday revealed some nibbled staghorn sumac and red oaks, as well as some floating chewed sticks. Interestingly, most of what they’d chewed down were stems that had sprouted up from stumps of trees the previous tenants had nibbled down. I wasn’t able to tell if they had a lodge, but it looks like there might be a spot in the thick Phragmites. The pond had a glaze of ice, and I also couldn’t tell where their food cache was, though there was a rather large log propped up against the outflow structure.

Red oak stump freshly chewed by beavers (Centennial Woods)

My strong suspicion is that this beaver (or maybe pair?) will set up shop and live in the pond for as short a period of time as possible before moving on in the spring, which is exactly what the other 3 beavers did in 2012. It’s also my hope that UVM a) doesn’t set kill traps for the beavers and b) does more to restrict access to the pond. We’ll see what happens.

Click for photos from the beavers in the retention pond

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