George,
Tom is right about all day and in the morning. The Ol' gobbler will call all his hens together first thing and then provide his services. He will then leave them around mid morning looking for more. If you are fortunate to find such a bird, you stand a good chance of bagging him. I have never hunted past noon, due to my states law so I don't have a clue about evenings.
Good Luck,
Stan