Remember the Color spectrum
Roy G Biv
Red
Orange
Yellow
Green
Blue
Indigo
Violet
Museums years ago found that they needed to display nocturnal animals so the public could see them. They found that nocturnal animals could not see the color red, and this is the color they used in the Viewing rooms.
Later on, scientists found that the rods and cones in the eyes of nocturnal animals are arranged in a way to make them color blind, and their brains are especially tuned to pick up movement vs color.
So, when choosing a light, choose the color red, IF LEGAL in your area. One poster brought up a particular good point in that they can see a shadow cast from red light. I would add that we played with this issue when we were doing so much hunting in Mexico for predators. First, 100,000 candle power is max we ever used, tight beam air craft landing lights. Million candle power lights seem great to a novice, but to an experienced hunter, coyotes see something going on, shadow, etc. Second, we would use darker red filters. Many newbies want to light up the whole world, and this is bad thinking. You only want to illuminate the eyes, so you hold the bottom of the beam at the top of their heads as the coyotes are coming in, then when you get ready to shoot, you drop the beam down where you can see the whole body. You never shoot at eyes.
We had other lights set up with only 35,000 candle power with red lenses used in tight cover.