Warning: This is controversial. No matter whose side you're on, this is going to be very controversial:
A surgeon in Vienna, Va., was recently arrested and charged with firing his gun in public - and with cruelty to animals. He fatally shot a hawk in the backyard of his home after he saw it eyeing a young squirrel, one that he and his wife had nurtured after it had been orphaned. The same bird of prey, apparently, had previously caught and killed an adult squirrel in the couple's yard. When the doctor saw the bird return and track the younger squirrel, he tried to chase it off using other means - none of which involved firearms - and then, when those attempts failed, he got his shotgun.
Was he right to fire his weapon in a residential neighborhood? The law clearly establishes he wasn't, and deems this a crime.
Was he right to protect the little squirrel as he did? Another law - in this case, the law of nature -establishes just as clearly that he also wasn't. The doctor's intervention unhooked one of the links in the food chain and disrupted the natural order of predation.
Is it criminal to want to save a life? This is what doctors do for a living, after all, with their human patients. In this case, the doctor had cared for the small helpless squirrel, raised and released him and, when he again fell helpless against the talons of the hawk, the doctor again intervened.
But is it wrong to take a life to save one? Likely there are many who would argue that the predation should have proceeded, uninterrupted. Likely there are others reading this (and at least one person writing this) who wouldn't think twice before doing the same thing.
There are no easy answers.