Report 19961: Possible knocking heard in Pictured Rocks National Lakeshore

We were walking in to see Miner's Falls and were approximately a quarter to a third of the way down the trail when we heard a loud banging of wood on wood.  At first we just looked at each other and kept walking.  Then we heard it again and it was a little louder.  We hesitated and I asked her if she heard that.  She said yes.  We looked in the direction of the noise and sure enough.  There was a stick banging back and forth between two trees that were in a growth of trees.  It was a large stick and you could see the end of it very well so it had to be sticking straight out.  I'd guess it was about six and a half feet up the tree you could see it.  Just before the banging stopped there was a glimpse of something dark that couldn't be identified.  It seemed to be standing up from leaning over.  As fast as that, the noise stopped and I wasn't able to see anymore.  My friend didn't even get the glimpse from her angle.  It was clear all the way around that growth of trees so whatever it was, went straight away from us on the other side of those trees. There was no smell or fear associated with this.  Just the banging and a glimpse of something dark that had apparently set that branch down as we were able to see it had been leaned up against the tree as the trail circled around that area.   We did not go up to the trees to investigate.