I checked the dam twice recently. Once on the 19th, and again today. I'm not surprised, but a little sad, to say that the dam has breached from the heavy snow melt and rain combination.
You can see in the second photograph that the middle section of the dam has breached.
I'll keep an eye out to see how long it takes to repair the damage.
The dam. 23 Feb 2014.
A field of stumps regenerating.
On the 19th, I happened to walk around the old dam site from 2011. That particular dam has been washed out and abandoned some time ago. I was on the right bank of the run, where many trees had been cut down and presumably killed by the beavers.
Happy news.
As you can see in these two photographs, most of the trees chose not to die, but rather to regenerate. You can find an interesting article about the process here: http://www.adirondackalmanack.com/2013/06/adirondack-forestry-stump-sprouting.html.
Stump sprouts.
Meanwhile, a couple videos of the ubiquitous fox and also a raccoon. Hope you enjoy them.
I checked the dam yesterday and noticed something interesting.
A section of the dam had failed. The bank on the left side of the stream failed. It was incised already, and seems to have failed. the failure point was just downstream from the dam, and caused about seven feet of the dam to collapse.
The beavers have wasted no time in repairing the dam. You can see the repaired section in the foreground of this picture. The sticks are newer and less weathered. You might also see that there are no leaves stuck in between the sticks as there are in the older section of the dam. Those leaves are an important part of the benefits of beaver dams. They provide food for insects. And those insects provide food for trout and other fish. And trout provide sport and food for humans. In one study, winter survival rates for salmon and trout was 2 or 3 times greater in streams with beaver dams than streams without beaver dams. (www.martinezbeavers.org/wordpress.)
Here you can see an earlier video of a beaver carrying leaves to the dam.
I've never been successful in capturing the beavers working on the dam. But I'm trying again. I hope to get some video of the dam repairs. Wish me luck.
Meanwhile, the usual suspects are active around the dam: beaver, deer, fox, squirrels, people, pet dogs, and raccoon.
And an Eastern bluebird. That's a nice reminder that spring is coming.
Soon the bluebird boxes in the park will be humming with activity.
The dam is in good shape. Maybe better than any of the four I've seen in the last two years. Let's hope it holds.
You all may recall the neat videos of a fox hunting that I
captured last month.
You can see the sequence of three videos here.
If you look closely at the third video, you
can just see the prey escape.
The fox failed to catch its prey. Talking with various
friends, the question arose; how often are fox successful in pouncing. Good
question, isn't it?
The answer depends, amazingly, on which compass azimuth they
are aligned with. It seems that foxes
have a magnetic sense. If the fox is
facing north to northeast, it's successful in 73 % of its pounces. Facing other
directions, the success rate is 18%.
A quick search revealed other examples of animals having
some sort of internal compass.
Water birds are most
likely to land in a north-south line.
Dogs are most likely to
excrete while on a north-south axis.
Migrating birds have a
compass map of the world, and use it to know where they are.
Cattle and deer tend to
browse on a north-south axis.
Loggerhead Sea Turtles
have a magnetic sense and use it to navigate.
Sockeye Salmon have a
magnetic sense, and use it to return to their spawning grounds.
Spiny lobsters appear to
have a" magnetic map" that they use to know their location in
the world.
That's what I found with just a quick search. There are
probably other examples. It seems pretty clear that many animals have the
ability to sense earth's magnetic field.
And this sense allows them to do more than recognize a
north-south line. Every place on earth has a unique magnetic map; a map that
some animals appear able to recognize.
So, after reading this, maybe you are curious to know what direction
the fox was aligned when it failed to catch dinner? Just a little bit south of west.
Failure.
Fascinating.
Hey, Jack, I'm not making this up myself. See below for some references.
And a special note to some young fans who left me a message via camera on 19 January 2014 at 2:18 pm. I do read my comments; and I did see yours. I also enjoyed your art installation. It was great. I look forward to your next one. I'm glad you're enjoying the blog; really glad.
More later.
"Pathfinders", by Doug Stewart., February/March
issue of National Wildlife.
I had a chance to check the camera and the dam last Saturday. There was snow on the ground, and I was
looking forward to seeing lots of track. I thought I might learn a thing or two about animal activity around the beaver pond.
I did learn a thing or two--just not what I expected.
What surprised me was that there was very little track of any sort in the area, and absolutely no beaver tracks.
I assume that means the beavers are doing what beavers do. That is, staying under the ice where they are safe from predators. They've already stashed a lot of food under the water, in the form of sticks. The entrance to their den is under water so, again, no predators can get at them when ice forms on top of the pond.
This drawing gives shows you how it works, and saves me a thousand words to boot. Can you imagine how our beaver family is happily and safely whiling away the winter under the protection of the ice. They've got a house, food, shelter--everything but high def TV. And no predators can get at them.
While scouting around, I saw a Great Blue Heron. Probably, it's the same one the camera picked up in this video on the 30th of December.
If you live in the Baltimore area, you may have noticed that it rained today. I thought it might be fun to look at the USGS stream data for Minebank run.
Whoa, look at that.
As it usually does during a heavy rain, the stream went in to flood mode. I imagined that the dam was probably overwhelmed.
I decided to drive up to the park to see for myself.
I was wrong. The dam was still there. Which was a very pleasant surprise.
breached on the 15th.
The dam was breached once already this month, on the 15th.
The beaver pair repaired it pretty quickly, and have been reinforcing it; apparently
On my last visit to the camera, I made several observations.
1--The last of the two dams has been breached. This is from the rain and melting snow that we experienced recently. As of this writing, there is more snow that will soon melt.
We'll see what happens.
2--There are two beavers in what certainly is a mating pair.I wish I could tell you that from my brilliant tracking observations. But I'm not that brilliant. Keep looking below and you'll see video proof that there are two.
3--Those two beavers have been very active. There are tracks and slides on both sides of Minebank Run. And they are very well used. There also are several medium trees cut down, again on both sides of the run. There are two food caches in the run, and thee were two dams. The first was washed away completely about two weeks ago. I hope the beavers rebuild the one that still stands.
Meanwhile, I got lucky, and captured some great video of the beaver pair at work.
This picture shows the camera as I set it up on the 7th. You can make out the camera attached to a stump in the left center of the picture. It's focused on a tree the beavers had already cut down. That tree is across the image in the upper half.
I captured a great series of the beavers working. You'll see that it didn't take them long to reduce the tree to almost nothing. They appear to have dragged to branches to the winter food cache in Minebank Run.
I checked the camera today, and was delighted to find a lot of fun videos. I plan to write an expanded post later this week.
Among the videos was this interesting series of a fox hunting.
In the first video, you can see the fox go into its pounce position. It has smelled prey, and is ready to get a meal.
The camera is set up to record video for 30 seconds. Then it stops and saves the file. After that, it's ready to go again. Sadly, that means that the camera missed the first pounce. Look closely, and you'll see that the fox is about two feet to the left of where it was at the end of the first video. Obviously, though, it didn't catch dinner. It is poking around and trying hard to find the target that it missed.
This third video shows another unsuccessful pounce. Look closely at the lower left and you can see the prey running away, and almost being caught. That's in the beginning of the video. Then you can see one frustrated, hungry fox.
I was fascinated to see these videos, and hope you enjoy them. Stop by Cromwell Valley Park soon, and perhaps you'll get a glimpse of the fox too. Wish it a Happy Christmas when you see it.
