The earliest I have ever harvested a bird was at about 6:00am. Bird basically flew down right in front of me, and the hunt was over. The latest would be at about 5:30Pm. I had worked this bird early that morning with no luck, and knew where he would be that evening. He was alot more responsive that evening, guess he was lonely. But I'd have to say that most of my serious action usually takes place between 7:30 and 11:00.