"I have another question though. I've heard stories of people going in extra early in the morning, well before sunrise and blowing an owl call or something to make sure the birds are still where they were when the person left the night before. Does this happen? Will turkeys gobble to, say an owl hoot or coyote howl, during the middle of the night?" [/quote]
I have had a few, but very few, people tell me they have had a gobbler respond to a locator in the middle of the night. Whether or not it is a common occurrence in some parts of the country?,...well, I have no idea, but I would doubt it.
In my experience, there is a direct correlation, however, to the amount of gobbling that goes on relative to the amount of dark/light at dawn and dusk. Here in NM with the Merriams we hunt, the likelyhood of a gobbler responding to a locator call definitely changes under changing lightness/darkness conditions in both the evening and morning. In the evening, our gobblers will start responding to locators about ten to fifteen minutes after sunset. They will respond well for about fifteen minutes, and then they will taper back off. After it reaches full darkness, it will be very difficult to get one to respond again.
In the morning, the reverse will kind-of happen,....no gobbling until some lightening of the eastern horizon, then some sporadic response to locators for a few minutes, then more reliable response until flydown, which here normally occurs about a half-hour before sunrise. Once the birds hit the ground, there will generally be some gobbling for a few minutes,...and then, except under the most ideal conditions, gobbling will once again taper off.
I have seen the same thing in other places with other subspecies, although the evening gobble has always been less reliable everywhere else I've hunted. As has been stated, the morning gobble almost always occurs,...at least in the places I have been.