I have a sort of covered lean-to between my shed and my makeshift greenhouse at the allotment. As I don't use this greenhouse until the toms are ready to go into it, I had not opened the door until this morning, at which point I realised there was a nest above the door in the corner. It looked as if it had been there a long time and there were no eggs in it, but since I was going in and out until September last year, I assume it must be a new one? Is there any way I can move it, and what sort of bird might it be?