In our third straight year of drought in Maryland a little while back, we were overrun with squirrels. I guess there were no acorns out in the woods. They ate all the plums off the plum tree, swarmed over the bird feeders, and generally made themselves unwelcome. I set a few Have-A-Heart traps and we began shuffling squirrels across the river, into the deep forest miles away. One Saturday, we hauled six of them. But more came to take their place.
I kept track of how many we caught; after we passed 60, I began to think that maybe we were taking the wrong approach. The squirrels were spreading the word; go to Paul's place, have a nice meal of peanut butter in the cage, then they take you for a pleasant drive across the river. We were probably a tourist attraction for squirrels, with transport in the trap their equivalent of some thrill ride.
At this point, I suggested crucifying the ones we caught in the traps as a disincentive to the rest, but my wife objected to this approach. Being in a semi-rural area where the neighbors mind their own business, I got out the shotgun and killed three of them one afternoon. We didn't see another squirrel in our yard for almost a year after that.
Paul