Tracking is a great skill to possess, though it takes some practice it is worth it. There's something about identifying the tracks of a fox, badger or otter and following them to their dens. But tracking doesn't just involve tracks, it also involves looking all around for signs of an animals' passing. You'll also find the "droppings" often enters the vocabulary.
Even the most insignificant items, such as a broken nut can betray the pressence of animals. Just by looking at how a creature has cracked open the shell of a nut or prised the seeds from a fir cone you can, with practice, learn to identify which mammal (or bird) has been feeding.