I opened up the top of the robber screen, unplugged the nuc I've been using as a feeder, and popped the cork off the vent I built it with. Almost immediately the sound went down, and by dusk I couldn't hear it anymore. I haven't been inside because Forrestcav and I have been having some grey, cloudy, weather. Chewing?
That's what I was thinking Alicia, but I came to accept the fanning idea. I am going to be surprised if that plywood is all chewed up. I made about 7 boxes, one without a vent in the back. They were getting in and out through a 2 inch by 5/16 hole in the front. In an effort to get feed to them I put another nuc next to it, an inner cover so they could get over to it, and a telescoping cover on top.
I had plugged the entrances with blocks of wood so I could control the robbers, and they started this. I have now covered the entrance of the feeder nuc with screen, opened it's vent.
The groove in this block fits over a 3/4 inch hole with no screen. I haven't really had any luck keeping the heavy rains we've been having out of the boxes, but I was thinking "Shipping container" when I did it. They're supposed to be up in a tree after all.
Joe, thanks for the offer, but I think it's just the reset switch. If I get desperate I'll go to my neighbor's. I'll tell you all what I find out.