I think a lot of folks are saying this, but I think the big point that many here are making is, at least for many of us, NO locator call at wakeup time. I would say a vast majority of my locator calls are used much later in the morning, early afternoon or after fly up time if he does not gobble on his own.
That is how I use them. We had a guy at a club I was in that would arrive just before daylight, and owl call like a maniac at one spot, if nothing answered he would move to another spot. If one did answer, he would move in on the bird hooting A LOT!. We called him "Hooty Who" because he relied on the call so heavily and was not real good at it. Twice I was sitting right near a roosted bird and he drove up near and from the road went to town and the bird did not make a peep until he moved on. I was still early in the game in those days, but that for sure taught me what not to do.