Last week, I asked if anyone could tell me what happened to this bur oak tree (Quercus macrocarpa) to lose much of its bark. There’s many reasons why a tree could lose its bark, so I tried to hint that I was “hiding” something in the provided pictures. What was I covering up? A North American Porcupine (Erethizon dorsatum). Congrats to @ttweakk on twitter for the correct guess!
This porcupine must have hung out in this tree all winter long by the looks of how much bark is missing. North American porcupines are generalist herbivores with a fairly variable diet. In winter, tree bark often becomes a primary food source, and porcupines can feed heavily enough from a single tree to the point of killing it. Because of the damage they can cause to trees, many people view porcupines as pests. But if this tree does die, it will create an opening that other trees can grow up in, contributing to a more varied and multi-layered forest.
Near the tree, I also found what appeared to be the porcupine’s den under a fallen log.
Porcupine pellets (poop) abounded inside.
Looking around the area, I didn’t see any other trees that seemed overly tasty to the porcupine. I wonder if the oak will produce any leaves in the spring. I think it might be a goner. I’ll have to check back and give an update. Maybe I’ll be able to give an update on the porcupine too. I consider myself as an expert porcupine spotter now (even though this is the first living, wild porcupine I’ve ever seen, yay!). You may notice the photos of the porcupine were taken in two different trees. I came back a few days later and still found the porcupine, which had moved to a tree a few hundred feet away that had no bark missing. However, a porcupine can have a 35 acre summer home range in Minnesota, so it might be tricky to find when more food is available.
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Man this fellow is really hungry. Around here they mostly munch on eastern hemlock branch tips.
I was way, way off with my guess. This makes way more sense!
You had a good guess though! I don’t know much about tree ailments and diseases, but figured that would be a guess.
While doing a little reading for this post, I found the different food preferences across North American porcupine populations really interesting. I came across one paper where some Minnesotan porcupines really liked hemlock too. But hemlock isn’t very common across the state.
Very cool! When backpacking in Banff a few summers ago, we were plagued by a porcupine at night… turns out we’d pitched our tent very near to a trail that it must have used nightly. We heard it overturning rocks and scraping along near the tent. Taught me to look much harder for even the faintest of animal trails.
Ha! Was that a little scary at first? Sounds almost like the porcupine was disgruntled that you were next to its trail.
It was a little scary actually. I had left my glasses in my backpack, which was strung up on bear ropes 1/8 mile from our tent. I’m blind as a bat without my glasses. It kept circling back and grunting in this odd-numbered repetitious way. We got up to pee in between its visits, and then we heard it lapping at our pee spots after we got back in the tent. Matt sat up for about an hour clutching the bear spray. About the fifth time it came by, it brushed against the tent and we freaked out and shook the tent as hard as we could, making as much noise as possible. It ran away and didn’t come back. At the time, we weren’t sure what it was, but we later ID’d as a porcupine from the vocalizations, and we saw several on the trail on that trip.
LOL. Glad it was only a porcupine. Reminds me of an encounter we had with skunks. It was at a campground, so I think they were used to people because they came right into the campsite. So, we had to balance scaring them enough so they would leave with not scaring them too much so they wouldn’t spray. Somehow we managed.