When I was in the Army in Malaya we had a special clamp that clamped onto the side of the No5 rifle or big Savage shotguns that housed a long 5 battery torch. A bit agricultural now with modern long beam bright torches but the light beam was zeroed in at 40 yards so that anything within that distance would get it! The bracket and torch were quite sturdy and these were used in ambushes so that as soon as the trigger was pressed, the light would illuminate, identify the target and open fire. You could open fire from the waist. As you can imagine, it was good fun just testing these things, shooting from the waist at targets to ensure good central hits
Assuming that your critters ain't going to shoot back at the lamp (the critters there were inclined to - if they weren't dazzled or running around like headless chickens.....) then that's a cheap option. Or even a laser will light up their eyes at night. They just sit up and wave at you as if to say 'here I am...., what's keeping you........?