Sunday, June 9, 2013

More Troubles for the Preserve's Beaver Colony

Julia swims in calm waters a few hours before the storm
Gentian and Tippy enjoy a playful shoving match on the day before the flood
On May 29th we had a tremendous downpour. In less than one hour, several inches of rain fell. The area’s streams - many of which had been barely flowing, were instantly transformed into raging torrents. Some streams at the nature preserve jumped their banks and one footbridge was washed away. All of the beaver ponds were immediately filled to capacity, but the major dams held. At May Pond where the beavers reside, the downstream side of the dam looked like Niagara Falls. The entire span had water gushing over it, but somehow that dam too was holding.  Despite how loud and intense the scene seemed to me, Julia, the adult female beaver, was quite casually floating in brown water of May Pond, munching on some poplar bark.
After the downpour, May Pond turned the color of chocolate milk
2 days after the storm the dam at May Pond did fail (talk about a delayed reaction) when a 15 foot span collapsed in the center of it. The breach caused a rush of water to head downstream and that in turn damaged the makeshift repair work that had been done on Secret Pond’s dam back during the winter.
May Pond as seen through the gap in the dam
Of course May Pond was much smaller that Sarah's Pond, which ruptured about a year ago and resulted in the loss of 4 beavers including May Apple, the colony's patriarch.  This event, as far as I could determine, was probably not lethal. At least Julia and the 3 one year-old beavers that constitute the known members of our colony were all accounted for following this dam break.
The normally underwater lodge enterance - now exposed
A major concern for beavers following an event of this kind is the state of the lodge. Unfortunately, the lodge at May Pond is now well above the water line and all of its entrances are exposed - which is not at all how beavers want it. Underwater entrances are what keep out the majority of predators as well as other animals that may be in the market for a den site of their own.
Julia makes her way up the stream channel that used to be May Pond
Just to put the frequency of major dam breaks in perspective: Those that read this blog may think they are very common, seeing as though we’ve now had 3 major breaks in one year, but in the previous 13 years at the nature preserve, we only had one.
Julia works to repair the dam at Secret Pond
Repair work on the dams at May Pond and at Secret Pond seemed to begin immediately after the breach. This time however, instead of experienced dam builders like May Apple, Blueberry or even Badger, the work was being taken on by the yearlings and by Julia. I’m afraid that this crew were not proving to be very proficient at the job. Julia is 6 years old, and obviously a very experienced beaver, but she's had little practice in dam building. In the past there had always been other beavers - mates or other family members to take care of that kind of work. But now here was Julia, in the early afternoon, working to rebuild the crude patch that was placed on Secret Pond's dam after it too was breached during the winter. She seemed to be working in earnest, but was easily drawn away from the task at hand by any number of distractions.
Gentian tries free a long branch in order to add it to the dam patch at May Pond
The yearlings - Gentian, Tippy Canoe and Tupilo were all working on putting a patch on the May Pond dam. It was proving to be an especially difficult task for them. They were cutting leafy honeysuckle branches, shoving them into place and plastering them with mud, but whenever they had a modest patch in place, the heavily flowing stream would carve a large gap below it - or would quickly erode the mud alongside it. It was clear that were getting nowhere and truthfully, their dedication to the job was less than awe inspiring.
The dam patch wasn't working very well and soon the yearlings gave up on it
Last year when Blueberry (now deceased) and Badger (now missing for 2 months) remade the dam at Secret Pond and simultaneously excavated a new lodge, they displayed the best of beaver engineering prowess and of perseverance. They worked round the clock until the job was completed. But they were older and more experienced animals. Given the situation as it stands, there is little chance that our current much reduced colony will have either Secret Pond or May Pond up to speed anytime soon.
A Gray Catbird hunts for stranded tadpoles and other tasty morsels in mud flats of May Pond
A Green Frog coming to terms with the fact that its pond habitat has disappeared
It seemed clear that the beavers’ only option was to abandon the site. Fortunately, we still had one pond in the beaver pond system that had an intact dam and a viable lodge with underwater entrances. Julia made her way up to the first pond, which is called Morton's Pond, and checked it over. That pond was first used by Julia's parents (Morton and Sarah) back in 1999. Julia had lived there herself as recently as the winter of 2011 - ‘12, but these yearlings had likely never seen it before.
Morton's Pond was the only good option and the beavers ultimately adopted it
Julia again happily munching Aspen leaves in Morton's Pond
After determining that Morton’s Pond was still viable and the dam (after some minor maintenance) would be able to support the small colony, Julia returned to May Pond to get the others. I happened to be at Morton's Pond when Julia and 2 of the yearlings came over the dam and entered the pond. They came in as a tight group – head to tail, like a beaver train. I've noticed that since this latest disaster they are engaging in a lot more family bonding than usual. They are being more solicitous with each other and also greeting each other with more enthusiasm.
Gentain and Julia feeding alongside each other
Dragging a branch back to the lodge at Morton's Pond
Tippy and Gentian feeding on Aspen leaves
So our beaver colony continues. With luck, during the course of the summer, the young beavers will continue to hone their work skills and come the next challenge they will be able to respond in a competent manner.
A House Wren nests in a dead snag over Morton's Pond
The male House Wren sings on top of the nest tree
Viceroy Butterflies mating next to the pond
Blue Flags bloom along the shore of one of the ponds

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