I teach a unit during my zoology course I call "animal gait analysis", specifically it revolves around various aspects of identifying and tracking animals; even scat analysis. The students really get into this unit and has quickly become a favorite among what I teach. It's a pretty relevant topic in that kids can actually use the knowledge they pick up.
The attached document is what I hand out to students at the end of the unit for identifying/keepsake purposes. I usually laminate them and print in color. If your teaching a similar concept or unit you can use this as a keepsake for the kids or even throw it into a full blown tracking lab if you have the available outdoor area. This is a great handout that allows kids to follow up on your content outside of class.