Question - Do you move the position of the CD's, move where they hang from? We have a wildlife biologist friend who seems to think that hawks are smart enough to figure out that the shiny things don't actually move, and he suggested moving them about frequenly. Does anyone who uses CD's move them around? Also, how many do you have in, say, a 20 x 20 area? Do they have to be like every 5 feet? 10 feet? I think my metallic pinwheels are doing the same job, I just want to make sure I have enough in there.