I got this along with the one for harvesting a wounded animal. Find a roe deer or small game animal. Stalk it and when the opportunity presents itself aim for a non vital area of the animal (I shot in the upper back/hip region). The animal will run but will leave a trail of blood, droppings and tracks. Follow them from the spot where you shot the animal and follow the highlighted tracks, blood and scat until the achievement pops. If you spot the animal and don't have the achievement yet just scare it off and follow it again. This will likely work for finding 100 tracks but I haven't accomplished that achievement yet.