Some of them definetly end up in the freezer....Some of them end up coyote food, and others are road kill and other natural causes.

As you no doubt know, the older they are the smarter they are. I'm sure some pick up and move, but I honestly believe that to be a pretty small number. They just become recluses, and don't move far from their beds during daylight. I'm betting if you had let's say....20 bucks around, at least 10 of them are still there....They're just hiding, and apparently doing a mighty fine job of it.