Man Found In Time Lapse Video Moves Very, Very Slowly

This is a section of a 24 hour time lapse video someone made. It's sped up to 8 times normal speed, but when he watched it back, he noticed that there was a man slowly drifting across the video "as if the wind was blowing him and nothing else." Is he a plant? Is he a weird guy? Does anyone know what's happening here?