Next, cover the lens of your lamp with a piece of red plastic. You'll still have enough light to walk or write by, and you'll be able to spot animals without startling them. The red light will be undetectable, plus it'll give away their position by reflecting light from their eyes back at you. You can identify many critters by the color of their eyeshine. In bodies of water, opalescent green gives away bullfrogs.
Movement is another clue.
Big and little brown bats, both found throughout most of North America, have surprisingly different flight paths. The flick of a tail is another sure sign of an animal lurking nearby. For many animals, the ears take over when the sun goes down. You can improve your nature hearing by concentrating on the sounds around you. On your next daylight hike, pause, close your eyes, and try to separate each sound.