Hey Mark...Haven't been on the forum for awhile...just picked up this thread. Changes in birds that aren't associated with anything external usually signal an internal change like hormones developing or something of that order. You've read the behavioral book by McDermott, make certain nothing you're doing is causing a negative effect first. If not, weight reduction is probably in order....slowly, just a couple grams at a time. You'll probably see improvement in just a small weight loss. He will display his aggression on the baggies first and then the fear response will decrease as he lowers. It doesn't take much for the Gos, so it will probably take less than you think to get him back, but don't go fast or you risk feather damage before hard penning. I'm no expert on the little guys (or the big guys either, for that matter), but I waited until the fear response got too far on mine and paid the price with a long delay in development. Good to see you're having so much fun! Isn't it amazing how attached we get?