Yes, it's all an illusion, this idea that you can choose to pick up those field mice or not. You, the hapless rodents, and the good fairy are locked in a web of causality that stretches beyond your control or understanding. Your conscious mind is a tiny ship on a massive and treacherous neuronal sea, the impulses to inflict violence emerging from mysterious depths you can not imagine with a force beyond denying, even though on some level you know it will bring your doom...
But choice still matters. Your actions free or constrain the lives of countless creatures in the field in ways we can't even realize. Just as my words to you, the warnings you've already received... these bits of stimuli are right now affecting what you will do next. And strangely, they become part of what you are. As you alter your own life and the relationships you have with small, terrified fleeing mammals, or an angry and disappointed supernatural creature who for some baffling reason is enforcing a bizarre moral code here in the wilderness, you are discovering yourself through time. Who is Little Bunny Foo Foo? Whoever he is, he has two more chances.
It's false comfort to think that you decide what your circumstances and the dark parts of your own brain are telling you. You're no more than a puppet deciding that he wants to move with his strings. But your mind, your actions, and finally your fate are you nonetheless, and no one else.
You are a goon, Little Bunny. Live like one.
(Photo of Sam Harris under Creative Commons license. Source: http://www.fritankesmedja.se/sam_harris_bara_vetenskap. Information here.)