One of the most important tool in proving the existence of Eastern Cougars are Tail Cameras. The Eastern Cougar Foundation, myself included use these motion detecting cameras in "camera surveys." How a trail camera works is, the device is mounted (on a tree, or other stable object) at about 2-3 feet off the ground. The camera has a sensor which detects motion, and sometimes it can detect heat. When the sensor is tripped because of something passing in front of the camera, it tells the camera to snap a picture. Simple enough.
The best way to set up a trail camera:
1) Find a place that has the potential for animals to pass by frequently. This would be somewhere the trail funnels the animal through.
2) Find a suitable tree. This is the hardest part in setting up the trail camera, because you need the perfect sized tree where the strap will reach but be in the best position.
3) Know how to set up the camera whether it is digital or film.
4) Wait! and know the battery life.
Here are some pics I got: