Finalists compete at the 2006 APF show
While hiking around the woods near my home this past spring and fall, I have heard branches breaking far up in the trees (30 feet or higher)-- one time up in a sycamore tree on May 7 and the other time up in a hickory tree on October 22. The location of both events is about 5 miles apart. In both cases, the tree trunks went straight up the first 25 feet or so without any branches and the trunks were massive (over 6 feet in circumference). In both cases, there was little to no wind so the movement high up in the trees was obviously discernible and suspicious. A dead branch (of good size, what folks call a "widow maker") fell to the ground from the sycamore tree. Only twigs and bark fell from whatever was making the noise up in the hickory tree.
Now I doubt whether a smaller animal-- such as a possum, owl, bobcat or raccoon-- would have had the body mass to break off the large branch. Perhaps an animal as large as a mountain lion or bear moving around up in the tree would explain the noises I heard and branch being broken up in the sycamore tree. But I'll concede that a smaller animal would have been capable of knocking down twigs and bark while moving around up in the hickory tree.
Now while I'm hiking around suspicious areas in the woods, I don't just watch where I'm walking on the path. I find myself stopping often to look up and down all of the sturdy "climbing" trees in the area.