Backyard murders

Half my family leaves today on a trip, and my father returns from his. The first thing he tells me is that a tiny rabbit was found in the yard, missing a head. We go to examine the scene but the body is now missing entirely. 

It could be a cat, a fox, or maybe a coyote but whatever it is my dad wants me to watch over the backyard and shoot it with a bb gun if I see it. Now if this were last summer I'd have the time but there are other things I'd rather do than spend my free time protecting a family of rabbits.