Blade sound passes overhead while photographing wildlife at night.

Arriving at 2:00 am. Sitting in a blind along Amite River, a very rural area of only hunting lands and gravel pits for miles. I came to photograph to white-tailed deer in the area on family owned land.  The weather was misty rain, windy, cool with complete very low whitish cloud coverage, moving north.  I could see fairly well up and down river. ( No details, it was dark.)  At about 3:00 am I was reclined low in a blind, facing north. (upriver) I heard a noise coming from  the north. I did not really take notice if it at first until it started gradually getting louder and louder. The sound was just like hellicopter blades . (Not at full flying speed but rather landed and idled down to a speed of one blade pass per second.) And absolutely no other sound. No engines, turbines or anything. Just the sound of the blades. The sound came from the north and went right over me and continued on down stream behind me to the south. The blade noise was so loud it was deafening. It never missed a beat as it came, pass over and continued south. When it seemed directly overhead I pulled my head down even further mostly as a reflex, for it seemed that low. I knew exactly where the noise was (just like a jet passing in clouds) but I could not see anything.  It really scared me and I just froze there waiting. As I sat there about five minutes later I heard the blade noise on the other side of the river heading north above the treetops. When it FINALLY got daylight I hiked back to my truck, (about a mile) and went back to civilazition. I no longer photograph deer at night.