One thing that I know but not sure if its the concentration or your electrical field. But a predator can tell when you there, they sense it. I will give two examples one with a red fox and one with a lion. Was walking a ditch on a breezy day back in the old country, wind in my face and I see this red fox curled up sleeping up ahead. Every now and then it would lift its head and look around, so I would give it a few minutes till it put its head down and move forward ( I am dressed in all white cause snoe on the ground) . Some where between 35-40 yards I stopped, already had the safety off, mounted that shotgun and pointed at the fox, a few seconds later it woke up and turned its head right at me, no looking around no nothing, it knew I was there....was the last thing it saw, 1 1/2 oz # 2, closed the deal.
The lion was the last one I took over my hounds in 2002, this was the lion that ate the 3/4 curl bighorn the night before, took most of the morning for me to catch up with the hounds, lion was treed in a steep canyon. I circled above them and came out right behind the lion at his level, that's how steep the mountain was, keep in mind he was 15-20 ' up the tree and I was 15 yards away from him. Wind was blowing up the hill pretty strong right in my face. I stood there for 3-4 minutes watching that Tom, he was faced straight away looking down at those two hounds, left then right he would look back and forth, keep in mind how long this went on...............me looking at him the whole time, seeing what a magnificent creature GOD made, all of a sudden, that cat shook like he had a chill go down his spine and he spun his head right at me.....he sensed me and boy did his mannerism change... He did exactly what I had seen red fox do when I was a kid....so is it the stare, the focus.............our is it like the HEC's guy says, our electrical filed??? There is some research that says birds can see the electrical filed to some degree.....been tempted to get a HEC's suit for wearing under warmer winter clothes................what say all of you?