Busy as a beaver

They are at it again.  Almost exactly a year ago, I blogged about the tree-felling damage beavers had done on the creek that runs out of Sucker Lake in St. Paul (click here to read that post).  Park personnel rectified that damage by removing fallen trees, and the creek was once again obstacle free for the mallards and swans that overwinter there.

But the resident beavers must have been busy lately, trying to dam up the creek for their own winter security, because there are even more trees lying across the creek this fall than last year.

beaver damage

Three sets of felled trees are blocking the passage of water down the creek, creating pools of stagnant water in between the jams.

beaver damage

One tree has already been cut down (and successfully fallen across the creek), and the creek side of another recently gnawed.  Beavers seem to have learned that they need to first cut the tree on the side they want it to actually fall before starting to gnaw away at the opposite side. Pretty clever!

beaver damage

I’m sure the heart shape of this cut is purely accidental, but it’s a nice touch.

muskrat

Upstream in the litter accumulation around the tree fall, I thought I found a baby beaver. Could be a muskrat, though.

Muskrats are only about 1-4 pounds; an adult beaver might weigh in at 60, so size would obviously be an easy way to tell which species it is. But how can you determine whether what you see is an adult muskrat or a baby beaver?  Here’s a tip from the Washington Post.

muskrat

Muskrats have smaller ears than beavers in addition to a naked, skinny tail (like this animal has) that is flattened vertically, rather than horizontally like the beaver’s big paddle.   So that makes this a muskrat.

Beaver and Muskrat happily coexist in slow-moving streams and ponds.  In fact, muskrats prefer the habitat changes that beavers make because it encourages growth of the vegetation they prefer.  In the long run, the environmental remodeling produced by beaver dams increases the number and diversity of plant, fish, invertebrate, bird, and mammal species associated with that aquatic habitat.  So, is it wrong to call this tree-felling “beaver damage”?  I wonder what park personnel will do this year.

12 thoughts on “Busy as a beaver

  1. Wonderful. That head and ear sure looks like a beaver’s. If you’d heard the slap of the tail, that would have helped, but perhaps immature beavers don’t do that either. Great photos. Great information! And fun to read!

  2. That’s my stomping ground! Well, mostly Vadnais Lake, but Sucker Lake is often a place I go. I didn’t realize there were any beavers in the lake. I’ll have to head up to Sucker Lake next time that I’m there and check out the signs.

    If you’re looking for beavers, I’ve had good luck at Crosby Farm Regional Park, the lake at the east end that’s easily accessible from the lot at Elway St and Sheppard Rd. When I’m there at dawn or dusk I’ll often see the beaver near the shore path there and hear a few tail slaps.

    • I think the beavers are actually in the creek that runs between Vadnais and Sucker Lakes. But never having seen them (just the fresh tree falls), I’m not really sure. Thanks for the tip about Crosby Farm — I should try that, although I am usually not out and about at dawn or dusk.

  3. Wonderful shots, Sue. It’s been quite a while since I’ve seen a beaver. They did a huge wetlands restoration project at my local marsh, which prompted the beavers to relocate to a more inaccessible (to me) location. I’ve stayed until past sunset a couple of times recently in hopes of seeing the beavers, but so far have had no luck. Fortunately for us, the beavers are not in a populated area, so they can do their own thing without causing any damage to property. For me, the tail is the only way that I can distinguish a muskrat from a beaver when they are in the water.

    • Good to hear — about the beavers being left alone to do their thing. I think I was biased toward thinking “beaver” in my ID because I had just been looking at all the downed trees. That and the fact that the little critters were so far away and in the shade so I couldn’t really see a tail with my naked eye (or in the camera viewfinder). That tail slap is a good give-away too.

  4. Pingback: The dam issue | Back Yard Biology

  5. Beavers are fascinating animals but I have only seen them in zoos. European beavers were nearly wiped out in France but are now being reintroduced from the remains of their population. I would not mind sharing a bit of countryside with beavers even if they cut down some trees. Amelia

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