Beaver Lodge Update

I wrote a couple previous posts about a beaver lodge being constructed on a lake near my house. Unfortunately, the beaver seems to have abandoned the site; I haven’t seen it around in ages, and no more progress has been made on the lodge. Today I climbed down the bank to take a closer look at what it had done before it left.

I’m disappointed that I won’t get to see it completed and coated in an insulating layer of mud for the winter, but oh well. Here’s my interesting fact about beavers for the day: you almost never find their scat. Why? Because they poop right in the water.

Anyway, I’m camping in the Porcupine Mountains again for the next two nights, but unlike last time when I was leading a wilderness trip for teenagers, I’m going with a couple friends and we’re staying in a yurt and bringing chocolate chip cookies and a board game. Yay mini-vacation!

Building a Beaver Lodge

A couple weeks ago I wrote a post about sitting and watching the behavior of a beaver on one of the lakes here, and I included this photo of the section of shoreline where it was piling up branches.

Over the weekend I was back at that spot to flip rocks for International Rock Flipping Day, so I checked on the beaver’s progress and took another photo of the same site.

Less a haphazard pile of sticks, more a beaver lodge taking shape. You can see that the beaver in question is working on taking apart the big fallen birch tree. Also, note how the big log running parallel to the shore, near the bottom of the photos, has been almost completely covered over by a thatch of smaller branches in the second photo. Eventually the beaver will cover the lodge with mud, which will freeze solid when cold weather sets in.

Beavers don’t hibernate, but since the entrances to their lodges are below the water level, once the lakes freeze over they’re iced in. They stockpile food ahead of time, dial down their metabolism so that they don’t need to eat as much, and spend the winter in their lodges and swimming underneath the ice. Lodges are generally built with a small hole to allow for ventilation.

I’ll be keeping an eye on this particular lodge this fall and winter, and if anything interesting happens I’ll post more photos. For more information on how beavers and lots of other Northwoods creatures survive the winter, check out the excellent book Winter World by Bernd Heinrich.

Beaver Behavior

I went for a walk around one of the lakes early this morning, along a trail that follows the top of a steep bank at the lake’s edge. At one point I stopped to watch the Hairy Woodpeckers working the dead snags above me, and while I was standing there I realized there were soft bubbling and splashing noises in the water below. Glancing down, I saw a pile of large sticks on the shore I was sure hadn’t been there a couple weeks ago… and a beaver, swimming slowly back and forth.

I’ve seen beavers a number of times before, but usually when I do they’re swimming away at top speed or slapping their tails on the water to express their irritation at being disturbed. This was the first time I’d had a good vantage point to watch one without scaring it off, so I crouched down at the side of the trail and spent about twenty minutes observing its behavior.

After completing several lazy figure eights, it wound up next to a fallen birch tree that was partially submerged in the water. As I watched, it dove repeatedly, for about ten seconds at a time. Each time its head would disappear, its tail and butt would waggle around on the surface (it’s hard to get a sense of what a big animal a beaver is when you just see its face sticking out of the water, but its big butt gives you a better idea), and I would hear a deep gnawing sound. Then it would pop its head up to scan the surface before going under again.

Eventually it came up towing one end of a large birch limb in its mouth. Maybe it saw me at that point, but if so, it wasn’t overly concerned – it placed the stick near the edge of the pile that was already there and then took off at a sedate speed for another part of the lake.

If you’re looking for the beaver in the photo above, it isn’t there, I took that picture of the spot after it swam away – I didn’t get a good one of the beaver itself. But it was a good way to start my Wednesday.