"Spoor" refers to any trace of an animal, especially a wild animal, by which it can be tracked. Sometimes the word is employed as a euphemism for droppings, pellets, or other scat, but it also applies to the likes of footprints, a bit of fur caught on a broken twig, the twig itself, even a lingering scent. Diligent tracking — or in this case backtracking — can often lead to a promising feeding ground.
Discarded skewers
Shanghai
(From a September 2006 visit)