There can be tracks from insects, reptiles, deer, opossum, pets, etc. Another type of animal sign is scat. Scientists often identify what type of animals are in the area by noting their droppings. Animals also leave signs behind when they eat. Insects chew leaves, squirrels and chipmunks may tear cones apart to get at seeds.
Some birds peck holes in trees and peck at the dirt to find food.
You may want to bring in some examples for the opening discussion. You can set up a desk with an apple that has been bitten and a sweater on the chair back. These are animal signs. Scientists use animal signs to tell them about what animals live where. The fur of a fox on some sticks may mean the fox uses that spot to scratch, or it may pass through here regularly.