Now I know why I was going through bird seed so fast.
This is what I saw out the window when I got home today. This little....sweet heart....was poking his little finger in the holes in the feeder and raking seed out until he found what he was looking for. When I interrupted him and went over to the feeder, there were easily two cups of seeds on the ground.
I wonder it THIS is the culprit that has been digging up my gardens?