Knocking in Erie County, Pennsylvania

In 1991 my mom had a polebarn built on some property she owned in the country. This particular weekend my brothers and sisters and their families got together for a picnic. It was around noon when we arrived and started setting up the tables and preparing the food. My one brother had purchased a moped that was in exellent condition which he kept there for anyone to ride. After about an hour I thought I would take my son for a ride. He was 3 at that time. We were the first ones to ride that day. I thought that it would be a good idea to ride back in the woods since I like them so much. There are parts where there is mostly good size trees, and there are areas where there is alot of tall saplings. though those are up toward the front of the woods. We were back there about 15 minutes When I heard the most GOD AWFULL scream I've ever heard in my life. The kind that will make the hair on the back of your neck stand on end. The first time I heard it, it was quite some distance away but still very loud. Being that the moped was like new it was very quite, and at times you wouldn't think it was runnig. The second time I heard the scream it was alot closer. I'd say maybe 1/4 mile. But only 10 seconds or so had passed. You have to wonder what can travel that fast in the woods and swamp. About another 10 seconds passed and it screamed again. This time it sounded like it was right near us. I really wanted to see what it was but then I thought could I protect my son. Whatever was coming was smashing everything. It sounded like it was knocking everything down that was in it's way. As soon as I heard that I turned the moped around and was trying to go as fast as I could. Many times I would have to help push the bike with my feet to keep it going. I told my son if anything happened to run as fast as he could the direction we were going, and to not stop till he got back to the polebarn. We finally got out of the woods and into the field. I was hollering at the top of my voice to get someones attention. But everyone was in front of the polebarn so no body heard me. All I could think of then was here I'm about to die and nobody will see anything. We got to the front of the polebarn and the reason nobody heard me was cause they had the radio playing loud. I told everyone what happened, and everyone had a good laugh. But no one would go back to see if anything was still there. I really wanted to see what it was, but I was not willing to go back by myself.