Just my take...Tree talk refers to all the calls a bird can make before fly down (for example, all the different calls you hear sitting beneath a large fall flock at first light), whereas pitting refers to a specific call of a hen, the nearly inaudible clucks as she wakes up. Like drumming, if you are more than 75 yards away with the wind in the wrong direction, you will miss these calls in the morning.
I can see how one call may make those soft sounds much better than another, especially slate. I have a small slate that makes those little calls very well, nothingI would try on my short box or glass calls.
