Microphone Goof???

I've watched this movie many, many times and a while back i discovered a goof, or at least i think it's a goof. It's in the scene where Will Howard (The squeezebox-player) is crawling away from the indian assault and hides in the basement. If you look in the top-middle of the screen while he's crawling in, you can see an object moving in and then out of the screen. I think it's looks like a microphone but it could also be a horse mouth, any ideas?