White light approx. 500' off the ground, slowly movingOn Monday November 21, 2011, at approximately 0615 hrs I was in rural Beadle County, South Dakota; approximately 2.5 miles north and 1 mile west of Cavour, SD. I was out deer hunting, sitting in a shelter belt, awaiting sun up.What I witnessed was a white solid light traveling west to east. This light was no more than 500 feet off the ground and travelling at approximately 20 mph. It appeared to have slowed down a few times and was slightly swerving as it went eastward. Due to the bright light and close proximity to the ground I was unable to see what shape it was; but when it went by it was completely quiet.I know this was no helicopter, airplane or weather balloon. Also, there were no flashing lights which are required on conventional aircraft.