DiegoD, air shooters in my parts seem to prefer the .177. I don't know how big the crows get in your area (got recipes?) and I really can't say at what point you will take on critters too big to kill. However, I often hear that the 177 out penetrates the 22's. Great thing about air shooting is that there are far fewer legal restrictions, and it is one heck of a way to get acquainted with marksmanship and learning trajectories. I'd be tempted to get one myself, but I have a 22 that shoots subsonics so well that I don't see the need to part with the cash. But I would like to hear how things work out for you!