I would also agree with all posts. Even the oldest, biggest tom will gobble but I think that it would take many years down the road to say that the gobbles are learning to be less vocal as I'm not seeing it. I've seen some birds in Wisconsin that were huge (27 lb or better range) that looked like flying tanks. They would gobble on the roost but would never come to call no matter what I tried. Those are the ones that never die by gunshot.