Also it could be something very small like a reflection on anything that is spooking him. Not whitetail, but on our duck lease, they kept flaring. We were covered head to toe and in a fantastic spot. As soon as the sun came up, they started to flare, but once sun came up, we limited out. The next day we saw that there was a small square of reflective tape on the motor that would reflect the sun as soon as the sun came up, but when overhead, it didn't reflect anymore.