I recently I decided that the very old flip top feeders I have had from a couple of trees should be replaced. The new ones were put up. It did not take long for the weather to have an effect, the timber warped and the bottoms fell out along with the plastic fronts. Blast - should have bought more expensive ones! So the two old boxes were cleaned up, given a coat of wood preservative (this done every other year by the way) and put back. So same boxes, same positions but the squirrels wont go near them. Had to clean them out as the peanuts and monkey nuts were festering. Had to do this twice now, so why wont they come near the feeder boxes any more? I have tried propping the lids open with monkey nuts - that does not work..
Is it that you haven't seen any squirrels since to reinstated the old boxes, or have the squirrels approached the boxes but have found something about them they don't like? I'm guessing it is not the wood preservative as you have used it before. I wonder if it might be it takes time for the smell of the preservative to disappear. Very puzzling as you'd think they would be desperate for food now.
2 squirrels are using the other squirrel feeders - the one where they go into a box and get the nuts from a jar screwed in from the side, but wont' go near the re-instated flip top ones. True they are coming less frequently so could be off looking for mates. I had not thought about the smell of the wood preservative - used a different make this time, so might be stronger - will have to do a smell test:)