For tree, ground squirrels, Rabbits, Crows (where legal), Doves(where legal), a .22RF is hard to beat at 75 yards. A 20ga shotgun is also great for bunnies, crows, doves, other game birds, and waterfowl. Shorter distances though, 30..40 yards. You can always move up to .22wmr or .17hmr. The HMR destroys to much meat IMHO.