Repeated event in Okanogan County, Washington

Every year for the past 20 years i have been going my family has a deer hunting camp outside of Winthrop, WA. We stay near Falls Creek and not in a camp ground, but up in the hills. The nearest hunter to us is probably 5 miles away. It is always a good time. In October of 2005, this last hunting season, we had a stange experience. My friend and I were walking down an old logging landing down to a creek bottom. We were talking and weren't being very quiet. When we got to within 50 yards of the creek, we began to here rocks being smashed together repeatedly. The sound was definitely rocks being slammed together, and it was loud. We figured it was right in front of us about 50-75 yards away. Our first thought was if it wasn't a man how could a bear slam rocks. We figured they would roll them over to look for food or something and wouldn't be able to hold them and slam them together at some points 4-5 times in row. There are no trails or roads to this creek. You have to walk through thick timber to get to it. Since we were the only hunters in the direct vicinity, we ruled out it was a person doing it. We could barely see anything down at the creek from where we stopped walking cause the timber was so thick. We walked a little closer to see if we could see anything and the rock smashing started up again. We thought it was time to leave and as we walked back to camp it stopped. The next morning we set out the opposite direction from the rock smashing of the day before. We went up the mountain this time, through a creek draw. I was on one side of the draw walking the edge as my friend was walking on the other side. The draw was wide enough to not hear each other when talking so we used radios. About 1/2 mile from the experience we had the afternoon before my friend radios to me as says he hears something and had a unnerving feeling something was following him just above him on the treeline of the draw. He could not see anything nor could I. He walked down into the draw and up to my side. We walked up the draw together about another 20 yards when we began to hear what sounded like 2 large sticks being slammed together about 3-5 times in repetition. The higher we walked the more we heard it. We could hear it parallel to us across the draw. After a few minutes we heard it parallel to us and then right away another set of stick slamming sounds came from about 100-150 yards just ahead of us on our side of the draw. We know we were being followed by something and there was more than one. Afer that we turned around and left. We left for home the very next morning.