RE: Red Lend Flashlights and Deer Hunting
Red/green lights are used primarily to preserve your night vision, since the eyes do not adjust as much as with white light.
They also "throw" less light on the ground, therefore are less noticable to any critter out there, even two legged ones. (Think military flashlights here)
If directed right at an animal, they will still see they bright bulb in whatever color they persieve it as.