I know most varmints cant which is why us coyote hunters use red lights for spotting, but can a deer see red light? If not I was thinking of putting a red lense into my headlamp and that way I can leave it on all the time when walking in and not worry about any animals seeing it and getting spooked.

I really dont have a anser for that.I think even if they couldnt see the red light.They may be able to tell that something is different from the lighter colored glow .This is a good question MN.

I've shined them with a red light before while pig hunting and they would just look my way and then continue eating. If they saw the light it didn't alarm them.

I can only offer this antidotal evidence. Last season as I was walking out of the woods after dark, I was using the "night vision" red light on my headlamp. I got to an area where I wanted to look for tracks, so I switched to the white "flashlight" setting. As soon as I did, a deer went crashing of into the night about 60 feet away from and behind me. I had passed this deer within no more than forty feet or so,with the red light on, and it hadn't spooked, though I am sure it saw or at least heard me pass, but as soon as the white light came on it high tailed it out of the area.

try a green LED light while walking in. Thats what i use and it never got em spooked.

Mostcrop permit hunters down hereuse a red filtered lens on a 400,000cp light to shoot deer,because it doesn't alarm them as much.So,I would say they do not see it very well.

I THINK THEY DON'T

if they see your reverse lights come on thats when the spook