Beaver Crossings

Karen Hamburger, a longtime volunteer with us, recently passed along another batch of trail camera video clips from our Derr Wetland Restoration.  You might remember seeing some of her video in an earlier post.

This time, much of her footage was centered around beaver dams.  There were quite a few video clips of beavers repairing dams or swimming past, along with otters, muskrats, ducks, and other wetland creatures.  However, Karen also captured some more terrestrial species using the beaver dams.

I often use beaver dams as a convenient bridge to cross a stream, and I know I’m not alone in that.  It makes sense that those same dams are important crossing locations for many wildlife species as well.  Karen’s trail cameras documented some of those crossings, including species such as bobcat, raccoon, coyote, and white-tailed deer.  See below.

In addition to wildlife, Karen’s camera also caught another creature crossing a beaver dam at our wetland.  Not once, but twice, she documented photographer Michael Forsberg working his way across the stream with camera in hand.

Mike has been photographing the wetland for many years, and has his own set of camera traps (trail cameras) at the site.  He has also been helping us capture timelapse imagery from the site through both the Platte Basin Timelapse Project and Moonshell Media.  This time, Mike got caught on the other end of the camera.

Beavers play important engineering roles in landscapes. Their dam construction activities change water flow patterns, flood low-lying areas, and create important habitat for many plant and animal species.  Karen’s videos are a good reminder that beaver activity not only affects wetland species, it also affects movement patterns of terrestrial species by providing stream crossings.  As beaver dam locations change, wildlife have to adjust their travel accordingly, and it’s fun to think about how those movement changes could ripple through ecosystems.  The location of a stream crossing for both predators and herbivores affects where those animals choose to forage, for example.  The fate of a plant or small mammal could well be decided by where a deer or coyote can cross a stream – which may be determined by where a beaver family decides to place a dam.  Fascinating!


Photo of the Week – March 6, 2014

As I posted a couple days ago, I spent some time at my favorite wetland earlier this week.  It was a cold, but very pleasant morning.  The sun was moving in and out of thin clouds, creating attractive light and a nice sky for photograph backgrounds.

A beautiful early March day at The Nature Conservancy's Derr Wetland.

A beautiful early March day at The Nature Conservancy’s Derr Wetland.


frozen wetland

An ice ridge formed along the edge of a flowing channel prior to the most recent cold spell.  It apparently caught blowing snow during last weekend’s flurries.



I assume the gap near the bases of these cattails was formed either by wind or by the relative warmth of the cattail stems, but I can’t explain the mounded ice.

Beaver activity was obvious along the stream that runs into and through the wetland.  Numerous dams are being maintained, and I found lots of recent tracks and marks from the dragging of sticks in patches of snow or bare sand.  The beavers’ slowing of the streamflow probably enables the surface to  freeze more quickly – to the detriment of waterfowl looking for a place to roost and feed – but the concentrated flow through the dams maintains small areas of open water where wildlife can access it.

Water pours over a small beaver dam.

Water pours over a small beaver dam.


Another one

The only open water left after the most recent cold snap was just below some of the larger beaver dams, though the ice was very thin in other places, especially above some of the more active springs.


Water over the dam

Water flows through the spillway of a dam just upstream of the open wetland area.  There are at least seven separate dams being maintained by the inhabitants of a single beaver lodge.


The beaver lodge is several hundred yards upstream of the main wetland area.

The beaver lodge is several hundred yards upstream of the main wetland area.

Beavers weren’t the only wildlife species active along the wetland.  Based on recent images I downloaded from our timelapse cameras on site, waterfowl have also been using the wetland in big numbers.  Canada geese, especially, have been abundant – especially before the surface froze last week.  Based on evidence found at the scene, they have continued to use the frozen wetland too…

goose feather

Goose feathers littered the frozen surface of the wetland



Here and there, tiny fluffs of feather clung to plants of all kinds.



Feathers were not the only thing geese left behind on the ice.  I can’t think of a better way to end this blog post then with a big pile of goose poop.  So there you go.

No beavers or geese were harmed during the making of this blog post.  However, more than 300 images were shot during a two hour period.