Yeah for the most part I don't hear much PM gobbling and I rarely try to locate them in the PM in that way. Most of the time I just sit very very quietly and do not move an inch, and if you're in the general area you'll hear em fly up.
However, one time last year at camp I was passed out on the couch about 7:00 pm or so and my buddy came runnin in from fishing and pretty much smacked me in the face to wake up. He said you gotta come out here and hear this. I stepped outside and on the mountain we hunt they were going absolutely insane. I have never heard so much gobbling in such a short amount of time. They were just on fire. It reminded me of "the wave" at a baseball game, it would start at one end of the mountain and just fire all the way down the line to the other end. It was pretty neat, but like you said I can count on 1 hand the number of times I've had em fired up gobblin in PM.