Thanks to Mike W and EMAW for cam advice!Mike W is dead on with the basic operations.
My suggestion is to buy a camera that has a sensor "sensitivity" adjustment. On my primos I can adjust the sensitivity (l/m/h) that will allow it to pick up the movement of branches or less sensitive to only pick up objects right in the center that are moving. I always max my sensitivity out to catch those little things on the edges. I do have to look through lots of pictures of grass and trees but for me it's worth it to make sure I get every creature large or small in the area. I have a moultrie camera that takes better pictures but has no sensitivity adjustment. I don't get near the empty frames but I also feel like I may be missing the small stuff. My next project is to set both cameras up together and test. Good luck.