The mystery has finally been solved! "And what mystery is that?" you may ask. Well, I'll tell you. As many of you already know, I have a squirrel feeder out behind my back fence. I typically fill it with deer corn, because it's cheaper than squirrel food. Usually, when I fill it completely up, it takes the squirrels about a week to empty it. Or if I only fill it halfway, it takes them 3-4 days. Here lately, however, after I fill it up, and it's been completely empty the next day. At first, I…