More observations

This week my son and I went out on Sunday afternoon and Monday afternoon to see what was to be seen. We made some interesting observations.

Is this a food cache? or something else?

First observation. Is it a food cache, or something else? Last week and again this week we noticed a pile of small branches on the east side of Minebank Run, between the dam and underwater food cache, near a slide where the beaver enters and exits the pond. Is it a pile of food left by the beaver? It doesn't look to me like a random thing. You might also notice dark, wet leaves on the side of the pile closest to the stream.

We put the critter cam in a place where we might observe the beaver eating, or tinkering with this pile. No luck. The plot cam setting revealed no activity. This, while frustrating, is probably pretty good evidence that the beaver is very nocturnal. The plot cam takes a picture every 30 seconds from about 20 minutes before sunrise for the next two hours. It does the same in the evening, ending about 20 minutes after sunset. the fact that the beaver did not appear in any plot cam pictures suggests that it is hiding away from people as the sun rises. There are a lot of people to hide from in Cromwell Valley Park. I understand that beavers are more or less strictly nocturnal in response to the number of people in the area.

Several eaten sticks are visible in this picture. 

Second observation. The dam has been built up since our last visit. Not a lot, but some. What struck us is that several of the new sticks on the dam have had the bark eaten off by the beaver. The bark on the bottom layers of the dam appear to be uneaten. I can only guess, but presumably building the dam is a priority for the beaver, so it limits eating until the dam is reasonably secure? Then it can strengthen the dam at leisure? This sounds reasonable to me anyway. I certainly welcome your suggestions.

Is this the start of a new dam?

Third observation. About 120 feet downstream of the dam my son noticed these pieces of wood lying across the stream. You'll note that some have been cut down by the beaver. Is this just chance, or the beginning of another dam? We'll keep an eye peeled and let you know what develops.

Fourth observation.  Some more trees are down, and farther away from the dam. We observed some trees cut down by the beaver as far as 600 feet from the dam. Like last week, the trees cut on the west bank were considerably larger than those on the east bank. The trees serve two purposes, food and dam material. The food comes from the cambium, the layer of growing, nutrient rich material under the bark. The wood itself is not eaten.  

Tree cambium is the layer under the bark that grows new bark and wood. It is rich in nutrients and is the part of a tree that beavers eat. It is primarily winter food for the beavers. they store a cache of twigs and branches under water. Beavers also eat various grasses when they are available. 

And, have you noticed that we have no pictures of the beaver from the trail camera? That is one elusive critter, isn't it? (And no Rebecca, there are no pictures of Sasquatch this week.)

This week the camera is set up overlooking the dam. It's set to take pictures in trail camera mode, around sunrise and sunset, as well as to respond to its motion sensor. More next week.....