Dr. Karl Miller and other researchers at the University of Georgia did a study on the whitetail’s vision and confirmed 2 things: 1) a deer’s eyes are well adapted to detect even the slightest movement; and 2) to get a good 3-D look at a strange and stationary object that might present danger (like you standing in the woods or looking like a blob in a tree stand) a deer has to shift its head from side to side and bob it up and down and stare at it from several different angles.
What it means as you’re hunting: When a doe or buck looks your way, picks you out as a potential predator, and then starts the head ducking and bobbing, freeze. When the animal stops and appears to have calmed down, keep still! He or she generally will try to fake you out a few times…head bobbing and stopping…bobbing and stopping… Sometimes a crafty old doe will do some head bobbing and then turn her head and look off to the side or away from you—still don’t move a muscle because she will spin her head back fast and try to catch you moving.
Only when the head bobbing stops for good and the deer relaxes and seems satisfied that you are not dangerous should you shift in your stand, get ready to draw your bow, etc. This might take 20 seconds or several minutes, so don’t move too soon and get busted.