Category Archive for ‘beaver’ at Beside the Stream

Archive for the 'beaver' Category

Progress on the beaver lodge

Published on November 25, 2008 in beaver. 2 Comments

I took these pictures of the newly refurbished beaver lodge and pond on November 19.

You can see that the lodge is substantial–Suzy thinks 9 feet, I’d guess 8 feet tall, and plenty wide.

The pond is clearly delineated, and it looks like it’s well established but it’s brand new. Don’t you like that fully peeled trunk on perimeter? They did.

This photo was taken at about the same spot on August 12,

and this shot was taken three weeks later. They’ve kept the basic outlines since then, and refined it.

This is a mid-August photo of their lodge, which was formerly an abandoned pile of sticks in a meadow.

This is taken from the other side of that same lodge on the same day. In mid-August, there was a few inches of new water around it. It didn’t look like much, but the beavers had big plans.

This is the same lodge from nearly the same point of view about 3 months later. Jessie is helpfully providing scale (though she’s very large). In fact, this pile is so big that the cottonwood trunk in the last photo has been completely covered. The beavers just patted on lots and lots of mud–you can see their handprints from last night’s work–and when the whole thing freezes it’s going to be impermeable.

To the right of the lodge is vast stash of twigs. They’re sticking out of the water, but they’re stored from the bottom of the pond on up: it’s more twigs than meets the eye. This is the beaver’s winter pantry, ready for the days when it’s too cold to go out for food. We have Thanksgiving on Thursday, but those beavers must be giving thanks every time they peek out their door and see that big stash of food for the winter. There’s nothing quite so cozy as a full larder.

Beaver, Wolves and Water

Published on October 6, 2008 in beaver and water. 2 Comments

When wolves were reintroduced to Yellowstone, no one anticipated how much they would change the landscape. It seems as though nearly all of the changes link back to the fact that deer and elk behave differently when wolves are around. They graze in smaller herds, and move more frequently. They’re harder for humans to kill, because they’re more watchful and live in smaller herds. And they browse less intensively, allowing cottonwood and aspen groves to replenish themselves for the first time since the 1920s when the wolves disappeared.

(I edited this wolf photo from this website, and the guy that posted it thought it was probably a remote camera photo).

Wolves hunt along the waterways, and so grazers no longer browse along the water’s edge. The big winner in this reorganized ecosystem is the beaver. Beavers have a long childhood: they live at home for two summers, and the third summer they move out and build their own dam and lodge. That summer when they’re three years old is the most vulnerable time in their life. They have to hide in streamside burrows until their new ponds fill in and their lodge is built. Where the streamside vegetation is sparse, they are killed.

When wolves were returned to Yellowstone’s Northern Range, the thicker riparian edge provided good hiding space for the three-year-old beavers, and the beaver population increased by 9 times in a decade. Nine times. If you want more beaver in the landscape, just add wolves.

Ranchers talk about the expense of wolf predation, and hunters dislike having warier prey. But in the arid West, one thing that everyone agrees on is that more water is a good thing. Wolves make the deer and elk nervous, it’s true, but more beaver means more wetlands, and more wetlands means a lusher landscape with more prey. Surprisingly, wolves (and the beavers that followed) brought more bird species, and denser bird populations, more butterflies and of course more soil moisture downstream. It is a strange fact that the same people who want wolves removed from the Western woods like water more than anything.

The very same people.

A midnight hike

Published on October 1, 2008 in beaver. 5 Comments

Suzy told me that if we hiked out to the beaver dam when the moon was full, we’d see beavers. I wanted to sleep in their teepee next to the river before winter, so last full moon I went to spend the night and take a midnight hike. There aren’t any photos because I don’t know how to photograph in moonlight.

I’ve never hiked in the middle of the night before, much less during the full moon. We went out at about 11, three ladies and three big dogs on a sketchy path through the forest.

The moon was so bright that we cast sharp shadows, and the tall cottonwood trees were limned with light. (This is a photo that I couldn’t take).

We went more than a mile, and then the three of us sat with our three dogs on the side of the river. (This is the second photo).

We were very quiet.

Before very many minutes passed, the beavers came to investigate. I heard many tail-slapped warnings, and lot of rodent-y swimming and splashing. I saw beaver heads as they swam across the pond, and at one point I saw three moonlit beavers swimming at once. (This is the third picture I had in mind).

It was a whole other world out there in the forest during the full moon, more magical than you’d think. And I finally saw a bunch of beavers.

A former beaver dam

Published on September 17, 2008 in beaver and water. 1 Comment

Here is a beaver dam that blew out in the high water of spring a few years back.

This is an auxiliary dam in the forest. This long structure is about two feet high, and it once made a pond that was the second of a series of three large, shallow impoundments. When the dam on the mainstem blew out, the water didn’t flow into the forest anymore. This series of ponds disappeared, leaving the dams high and dry.

I asked the dog to sit here so you could see how big these cottonwoods are: this old dam was the site of some serious beaver work.

She said, That tree is pretty big and this bole is really stupendous… but enough lollygagging around; it’s time to move along.

Beaver and water rights

Published on September 11, 2008 in beaver and water. 6 Comments

The right to use water is private property in the West, and no one is allowed to use water without buying water rights first. This means that beaver are water thieves: all of the water they impound is actually owned by someone downstream, and by gum ranchers aren’t going to be thwarted by some damned rodent. In Colorado, beaver (like prairie dogs) are classified as pests.

I agree that it looks as though beaver are water hoarders, taking more than their fair share of a scarce resource. But with water, it’s often true that what’s going on underground trumps what we see on the surface.

This illustration is by Steve Grannes, University of Minnesota MS Agricultural Engineering 1984. Here we have two streams coming straight out of the page, and let’s pretend for the sake of this discussion that they’re several miles apart.

When you add a beaver dam to one of the streams, it backs up water behind the dam and more water seeps down to the groundwater. This dam actually raises the level of the water table underground, which increases the flow of springs and streams in the surrounding area.

This means that beaver dams upstream should actually increase the flow of water downstream: add beavers, and you get more water in the watershed, not less. And a three year research project completed in 2006 shows that is exactly what happens. In the Rocky Mountain National Park, researchers found that ponds created by beaver dams in the Colorado River Valley raised the water table downstream, and increased the level of soil moisture far below the dams.

What is true in theory has been shown to be true in practice. In arid regions, beavers don’t steal the water in the river. Instead, their dams enhance downstream flows.

When ranchers insist that beaver populations or prairie dogs populations imperil their livelihood (as everyone knows) I can only say that when it comes to water, things are seldom what they seem,

or,

who you gonna believe: me Dr. Cherie Westbrook, or your lying eyes?

(Beaver Symbol, Pacific Northwest)

Time: Three Weeks

Published on September 8, 2008 in beaver, time and water. 1 Comment

The beavers have been busy.

Three weeks ago, there was one full dam and one half dam on the river.

Now the original dam is much more substantial, and the second dam downstream has been completed.

Three weeks ago, this dam spanned the river, but the water on the left side was just a few inches deep.

Three weeks later the dam is much higher. The log stuck in the pond in the first picture has now been incorporated into their structure, and the pond is turning into a nice swimming hole.

This second dam downstream was solid on the right side but faded out to nothing on the left side–it was a half span.

Three weeks later, the dam goes all the way across the river, and the water is backing up nicely.

That seemed like a lot of work to me, but it turned out that the serious construction is going on nearly a quarter mile to the right.

Three weeks ago, a sheet of water was spreading across a meadow.

This picture was taken from nearly the same location as the previous shot–it’s same tree on the left. As you can see, those beaver have built a completely new dam here. I’m impressed by their industry. But I suspect their response to my praise would be a beavery equivalent of: Honey, it’s not our first rodeo.

A new beaver dam

Published on August 27, 2008 in beaver and water. 2 Comments

Suzy took me to see a beaver dam that was built in the last few weeks. You can see from my big dog that it’s no more than a few feet high.

This is a second dam downstream, and it stretches halfway across the stream. You can see that the beavers are using stones as well as sticks in their construction. This is a classic high altitude, snow-fed stream. See the wall of stones on the left? It’s about six feet high, thrown up when the water is running high during spring melt.

At first glance, it looks like this dam starts at this end of the stream, and ends at the other side. Instead, it’s a small piece of a humungous engineering project. The pond behind the dam isn’t very deep because it’s a part of a larger scheme to move water to the right.

The dam doesn’t end on the other side of the stream… it goes on and on and on. Here the beaver have patted up a rim of mud to hold in the water. Look closely and you’ll realize that this edge is weeded–that’s the only way it’d be so clearly delineated.

Farther along the same dam the mud is shored up with sticks, and it still goes on.

In some places along the dam, the water is less than knee height. In some places the water is nearly waist deep, and my dog has to swim.

This dam isn’t very high, but it is exceedingly long. After we bushwhacked hundreds and hundreds of feet we realize this couldn’t be new construction. The beaver are taking over a spot that had been dammed before. And sure enough, after crossing over the newly filled pond we found an old lodge that was reoccupied.

I bet this lodge was once surrounded by water. Looking out from from the lodge towards the dam,

you can see there’s a lot of newly impounded water. The dam is all the way back at the big cottonwood tree, extending hundreds of feet to the left, and I think to the right as well.

This is the meadow to the right of the photo above, with Jessie standing in 6 inches of water. If you look closely, straight back from Jessie there’s a silvered old stump of a tree that was felled by beaver long ago.

There’s a new sheet of water moving across this land. If people’d just let them build, these beaver will be making some big changes around here. If you want to see the biological complexity of an acre increase right in front of your eyes, add a pair of beaver and step back.

A drained beaver pond

Published on August 23, 2008 in beaver and water. 1 Comment

Here’s a little beaver pond that I drive by regularly. It always looks pretty much the same to me, so my last photo there was April 18.

The pond was there yesterday, and today it is drained.

The dam was breached and the beaver must be gone or they would have fixed it. You can see from the height of the pond walls that this dam has been here for a long time, and you can see how it increased the complexity of the landscape. The geese and herons in the April post won’t be here next year.

I’ll come back with mudboots to scope out the broken dam, and in the meantime I have photos of big new beaver dams downstream, which I’ll post next week.

Beavers move in, Part 2

Published on May 16, 2008 in beaver and water. 1 Comment

We know that the beavers moved in because of their nighttime handiwork.

and it’s pretty easy to see where they’re staying. It’s a streamside burrow with two entrances that they live in until they build their dam, fill their pond and build a lodge. It’s their starter home.

The main entrance is right in front of you, made of peeled branches woven together.

The other side of the same pile shows a second entrance, while the beaver’s backdoor route is all the way over by the pile of peeled sticks at the far end of the bench of soil. There’s likely an underwater entrance on this end, and a series of underground rooms dug from here to that far pile.

This is the back door entrance on the far end of the bench, with an underwater entrance on the far end as well. The beaver’s first rule of home construction is: always have an alternate exit. Some animals fight off intruders, but beavers build a back door instead.

This pair is in a streamside burrow for now, but they have big plans. At night they’re consumed with construction problems, but during the day when they sleep they might dream of their dam and a litter of kits. Of the day when they have a proper lodge in their own pond.

This might be the beaver’s dream.

(This lovely illustration is from a book written by the Islamic scholar Harun Yahya titled Devotion Among Animals: revealing the work of God Ch.2 Awareness in Animals: One of the dead ends of the theory of evolution, Fig 5.) (I’ve gotten in trouble for using this illustration in lectures because people assume that I must renounce evolution to read antievolution tracts, but honestly, I’ll read anything.)

Beavers move in, Part 1

Published on May 14, 2008 in beaver and water. 5 Comments

A pair of beavers started engineering this area this spring. This is the view from one end of their clearing

and this is their clearing from the other end.

Without exception, all of the cottonwoods have been cut to fall at right angles to the river. I think at least 30 big trees–between one and two feet in diameter–have been cut here. There are hundreds of little trees gone, but you don’t notice them because they are taken away.

When they cut big trees, it’s a multi-step process.

First, they sit up on their hind legs and chisel their way around the base of the tree until it topples.

Then they go up to the top of the trees and trim off the branches from the top down.

Sometimes the tree doesn’t fall just the way they intended,

but mostly it goes exactly as planned.

This clear-cut is as deliberate as if someone cut this wood for a lumber mill (although since it’s cottonwood, no one would’ve bought it, and the beaver do a cleaner clear-cut than humans: they don’t leave slash piles that need to be burned).

When you consider that this is a project that likely a new pair started this spring, you can see that ”busy as a beaver” might be nothing but the truth.

I have a particular fondness for beavers. I am probably the only person you know who keeps a stuffed beaver in her bedroom

which is why you’ll hear more about beavers tomorrow.

Beside the Stream