Sunday, December 4, 2011

November 25 to 27, 2011

November 25 it warmed up again today. All the snow and ice melted which seemed to make the Deep Pond dam leak. We had 2 inches of wet snow preceded by a quarter inch of ice.

Maybe the ice on the pond makes it harder to pack mud on the dam, or dulls the beavers' ability to sense leaks. Perhaps I better phrase that last idea better. I’ve been in the midst of the river freezing a few times -- in a boat of course, and found it a chaotic and energetic experience. After it forms ice might seem solid, monolithic, quiet, but the process of becoming ice is anything but that. Beavers swim in the water as it freezes; swim out of their lodges and find ice over their head. How can human senses really fathom that? Winter simplifies my life in the woods. It probably complicates a beavers’ life. Not that I had much time for such deep thinking today. I went out to the valley the beavers left to continue sawing up the maples they killed into logs suitable for hauling and splitting. But first I had to admire the depth of water now in Boundary Pond.

The green grasses that grew up at the end of the summer on the last of the pond bottom exposed as the pond water drained through the hole in the dam was getting flooded once again.

I didn’t check the dam where obviously the hole in it is getting clogged with debris draining from the pond. I still fear that poking around the hole will only make it worse. Meanwhile, celebrating that deer ticks were no longer latching on to us, Leslie trimmed some trails, and in the process forced a young porcupine higher up a small pine tree.

November 26 we had a warm night, in the 40s, followed by a day with temperatures climbing back into the 50s. I headed down to my work in the valley, and soon found deer ticks climbing up my pants again. I knew Leslie didn’t want to be bothered with ticks so I tracked her down before she waded too far into fields. Sticking together helps find ticks sticking to us. We went down to check the slope of the Deep Pond where we saw a beaver go into a burrow. There were muddy trails up the slope and into the brush.

And I saw where the beaver ignored the larger branches of a honeysuckle for smaller nips.

I can only think that the nose directs this beaver to what it cuts. Eyes would be too big to result in such a low, almost unnoticeable snip or two.

Then I got to where I could overlook the burrow. The water was a few inches higher than it was a week ago. There was a green stalk where there wasn’t one before. No new mud. It more or less looked the same as it did a week ago.

Leslie moved on ahead and up on the crest of the slope in the middle of another path the beaver and, we presume, other animals have used, something had dug down into the dirt to a root. Deer eat roots too, as well as beavers. There were no prints from any animal.

Down in the water there were root fibers and stalks, remnants of this beaver’s usual meal.

We still haven’t seen evidence of the beaver gnawing bark off a tree. However, as we looked across the pond back at the dam, we saw what looked like a log floating behind the east end of the dam. I walked over to take a closer look and on the way I noticed that the higher water in the pond had brought the beaver to a clump of willows up from the pond almost at the dam. There were trails up to the clump and I saw that some willow shoots were nipped.

When I got next to the dam, I saw that what I thought might be a cut log was only yellowing cut grass stalks floating in bunches behind the dam.

Years ago we could walk along the dam but the honeysuckles there have thrived, even more than they usually do, thanks to the increased fertility of the soil forming the dam, thanks to beavers heaving mud laced with plants up on it. Unfortunately for the beavers, they don’t eat honeysuckle bark, except under extreme conditions. Unfortunately for me, honeysuckles seem to grab all the surrounding air when they grow making it difficult for me to squeeze through. So I walked below the line of honeysuckles. The ground below the dam was not as wet as usual at this time of year thanks to the beaver’s repairs. I got a good photo of a portion of the dam that I tried to repair one. Thanks to several muskrat tunnels that had gotten out of hand the dam gave way there and the pond lost two feet of water. Working from below the dam with logs and a spare plywood rectangle, I fashioned a patch and imitated a beaver to the extent of wading into the mud behind the dam and shoveling some up on the dam. Didn’t work, at all. A few months later a beaver moved into the pond and repaired the dam. Looking up from below the dam what the beaver did doesn’t look like it should do the job -- certainly not as well as a plywood rectangle. Looks deceive.

However, water is leaking there. Farther along the dam, there seems to be other weak areas with leaks. I didn’t probe to see exactly where for fear of making the leaks worse.

Perhaps I should have more faith in the dam repairing skills of beavers. It is not true that they react in Pavlovian fashion to running water and must stop it. The Swedish scientist who published that manipulated beavers he captured from a river that Swedish engineers would frequently flush like it was toilet. Rather than labeling beavers as engineers, one might get closer to the truth by saying that they practice a religion in which they worship by bringing trees to the earth and raising mud to the heavens. So up I went to admire their devotions.

As has been the case for a week or so, the beaver seems to be pushing up one or two heaves of mud each evening.

And I must say, looking down on the mudded dam, it looks impregnable, but, it is still leaking.

I also admired a bit of vegetation the beaver rooted up but didn’t eat. How it can find such bright greens at this time of year is a marvel to me.

There is a small pool of water a few yards up from the west shore of the pond, that I periodically go over to check because over the years beavers have found things to eat there. I saw that the beaver cut what, for it, was a sizeable willow, maybe just over an inch thick at its base.

However, there aren’t many more shrubs to eat in or around the pool.

What beavers cut down over the years hasn’t grown back yet.

November 27 we went for a hike to check on the East Trail and Audubon Ponds, and since the ticks are active again, we stayed on the trails as best we could. We got up to our usual perch up on the granite ridge north of the East Trail Pond, and after sitting there a minute or two in the pine straw, I saw a deer tick climbing up my leg. So I went about my observations and Leslie looked for snakes sunning themselves on the rocks. At last, I can see logs stripped of bark in the beavers’ cache next to their lodge.

Looking down at the otter latrine from the top of the ridge, I could see that otters had not been at there since my last inspection. I went down to take a close look. There was no hint of the smell of otter scats. Plus I noticed that the scent mound looked deflated. Beavers make their lodge with logs that don’t shrink (well, maybe in a year of two) but otters make their scent mounds of grass and they don’t last long.

I took a close-up of one of the most recent scats -- a week old? There were fish scales in it.

But the proportions of fish scales to je ne sais quois pas was much less than usual. Frogs must have been the principal fare. Now they are secreting themselves for the winter which may explain why the otters have stopped coming here. I walked along the north ridge to the west. When the pond had ice on it, I could see how the beavers used the northwest corner of the pond. With the ice gone, I can see the bottom of the pond and the clear bottom of the southwest corner gives the impression that the beavers are spending all their time there.

Back in late spring when turtles were active I saw a good bit of oil sheen on the water just off the north shore. I saw that again, not sure what causes it, especially since both plants and turtles are subdued now.

Then I got a good view of the trail the beavers have made up the slope northwest of the pond.

Once on the trail, I took a photo looking down. Of course, all land mammals make trails when they forage, but beaver trail are always more striking because beavers use the same trail over and over again and it is easy to see what they are eating or leftovers from what they ate or carried off to eat. Tracking any other animal is more challenging, however.

I also took a close look at the big tree that fell into the pond around November 15th that the beavers have been dancing around, so to speak. They have trimmed and hauled all the branches, and now are slowly gnawing the bark off the parts of the branches they didn’t cut and now have started gnawing the bark of the trunk.

I’ll have to check my notes because I did see this tree when it had leaves. The trouble with my unscientific cataloguing of these doings is that I lose track of my initial identification of a tree. Leaves help. I assume this is a red maple and since the beavers are slow to gnaw into bark that is so convenient for them. Many beavers don’t cut red maple at all, but the beavers in this family have cut, trimmed and sometimes stripped red maples for years. An expert may be able to identify the trees I’ve observed just by looking photos of the bark and wood, so all my work may not be in vain. The next large tree that will probably fall near the pond is an ash at the foot of the diminishing ridge west of the pond.

As I continued around the pond, back on the trail, I took a photo of the last big tree to fall, a red oak, which got hung up in other trees. Gravity may slowly bring it down so I want a photo showing its current angle.

While making the point that the beavers here are gnawing trees of all sizes, I’ve not kept up with their gnawing on the tree roots. They keep expanding their gnawing of the roots from an ash tree with twin trunks, but it's not that their incisors follow their noses down the root to ground. They've started gnawing a root that surfaced on the ground. Perhaps it comes from the ash, or it might come from the smaller maples just east of the ash trees.

I found myself paying close attention to the recent heroic labors of the beavers. They almost completely trimmed and stripped the sugar maple that fell along the ridge about a month ago. I tried to see why they didn’t cut two large branches at the end of what remains of the tree. Given what they had done to the rest of the tree, I didn’t think it was from fear of falling over the ledge. I wondered if a section of dead wood at the base of the branches, probably dead from old porcupine gnawing, deterred the beaver from cutting it off.

However farther down the trunk there is another branch they didn’t cut that leans a bit over the ledge. They did strip the bark off it as much as they could. So I think the beaver doesn’t cut the branches for the very good reason that it realizes it has to put weight on the branch while cutting and when the branch goes the beaver may tumble.

Next to the maple are two or twinned red oak trunks that the beavers seem to be gnawing somewhat haphazardly, probably because the trunks are too close together to conveniently get around.

Well, I was finally approaching all these trees like a beaver. Instead of gawking at their height or length, I was nosing down at the bark. The stump of the stocky maple they cut which I thought was an old job came back to life. The freeze and thaw got its sap running. The pale stump is now almost reddish brown from the sap. Plus, perhaps thirsting for the sap, a beaver gnawing into some more bark below the cut finding a red seam of inner bark there.

There were flying insects lighting on the sappy wood and I tried to get a photo of them, in a vain hope of being able to identify what they are, but if they are in the photo below, they are a blur. I share the photo because it looks delicious.

Farther down the pond I saw a smaller maple, just cut. No sap running there, yet. The beavers hauled the cut trunk down the slope.

Meanwhile I was late for my rendezvous with Leslie who didn’t see any snakes. I quickly took a photo of the trimming the beavers did on the smaller tree they cut during the snow fall a few days ago.

Then we headed to Audubon Pond, or at least I did after Leslie decided she did not want to face a stiff, somewhat cold west wind blowing down South Bay. I still look for otter scats in the lower latrines on the north shore of South Bay, saw none today and haven’t seen any for weeks. When I went up to Audubon Pond coming to it from the southeast, I saw a line of trees that the beavers just cut.

Two red oaks and a small maple, I think, and beavers had cut most of the branches and cut a large log off one of the red oaks.

Then farther down the trail to the causeway I saw that the beavers were in the process of cutting down a pine tree.

They are gnawing into the trunk so I expect they want to cut it down and get to the branches. We’ll see.

I walked down the embankment to the check on the growth of the cache outside the beavers’ burrows into the bank. I am challenging myself to try to identify what trees the logs in the cache came from. Very difficult.

Several of the logs look rather old. The beavers probably dredged them up from the pond bottom. The beavers are bringing mud up as well as logs to cover the grassy bank above the burrow. I can’t say that any shag-bark hickory, red oak, or ash branches the beavers just collected were up on the bank. So they must be sunk in front of the lodge.

Then I went back down to check the otter latrine above the entrance to South Bay, which the otters have been visiting. There was no fresh scats, just the same scats I saw there 12 days ago, easier to see since the wind blew some of the leaves away.

The photo below shows a grassy slope with leaves arrayed in patterns easily explained by the shifting winds. Yet I can walk around the leaves, and, in my mind, recite a short history of otters in South Bay since the leaves began to fall. Until I see otter scats, such recitations are pure fantasy.

I went back to Audubon Pond where the beavers’ activities are writ large. When I was here on the 22nd I saw from afar that the beavers were girdling a large ash tree in the woods off the southwest corner of the pond. I got a closer look and saw that the tree I saw then was now completely girdled and another a few yards was getting the same treatment. There was more gnawing on the north side of the tree, not in the photo, so I would say the tree is almost half girdled.

Beavers generally do a complete job of girdling a tree, gnawing off all the bark within reach and gnawing the bark off exposed roots. Then there comes a period when it is hard to tell if deeper gnaws are the beginning of their effort to cut the tree down or just a reflection of how tasty the last bit of inner bark can be to them.

I took a close up of the girdling that gives a hint of how many times the beaver gnaws over the same patch of wood before it gets all outer and inner bark off.

The beavers are cutting down smaller trees in this section of the woods, including two ironwoods. They often don’t gnaw much of ironwoods, but they did cut branches off these two trees.

The sap is running up in these ironwoods, and some bugs enjoying the sap didn’t pause long enough to get into the photo.

Deeper in the woods, the beavers are cutting tree in and around a vernal pool, which thanks to the wet fall has plenty of water in it.

They had cut a tree here a few weeks ago. I didn’t see any evidence then of a beaver relaxing in the pond and nibbling sticks. I didn’t see any evidence of that today. Then I went down to the big ash the beavers have been girdling for a few weeks. I would say that they are definitely aiming to cut it down, except that one cut is high on the trunk, because they evidently stand on a downed log as they gnaw from that direction.

Then standing on the ground, on the other side of the tree, they are cutting into the tree a foot lower.

There must have been a little sap running in this ash tree because I saw several flies on the gnawed wood, and managed to get a photo of one.

When I checked the smaller ash nearby, that the beavers have cut down, I noticed that what I thought was a stripped log next to the almost completely stripped trunk of the tree, was actually an exposed root that beavers also stripped of bark.

I assume that the root ran back to the ash, but on closer look, I think it comes from a clump of shag-bark hickories. The beavers have cut down the smallest of that cluster of trees, and cut and hauled away the trunk and branches.

The trail the beavers use to get to this work is now running with water, draining the vernal pool a bit deeper in the woods.

Looking back from the pond, as grand as the beavers’ gnawing looks up close, from a distance, what the beavers are doing may hardly be noticed once the newly expose ash wood loses its glow.

Closer to the pond, the beavers are in the process of cutting down the 5th shag-bark hickory. One of the others they cut is not quite in the photo below. The one they are cutting now is bigger than the others and, if they cut it down, will rank as the biggest I’ve seen felled by beavers.

The freshly gnaw hickory had more flies on it than the freshly cut ash.

So far, after a hickory falls, the beavers cut off some of the branches in the crown and a log or two off the end of the trunk. The beavers did that to the last hickory that fell.

Instead of walking around the north end of the pond, as I usually do, I went back around the south end of the pond to get some photos of the beavers’ work on the northeast corner of the pond. Here too they are girdling the largest of the ash trees, which has twin trunks situated so it might be difficult for the beavers to cut them down.

When I was here on the 22nd I took a photo of the trunk of the large choke cherry tree they cut down. Today, I got a photo of the end of the trunk. The beavers have cut off branches but haven’t stripped the bark on the trunk.

The first ash tree the beavers cut down fell up on the mown field leading to the causeway forming the east shore of the pond. A month ago the trunk was 30 feet long and, since it didn’t completely fall to the ground, Leslie and I could sit on it and bounce on the end. The beavers have taken away about 20 feet of logs, and stripped most of the rest of the trunk.

By staying on the trails, we avoided getting as many ticks as we have been getting. I picked three off my pants.