It's called survival of the fittest, and the bird that Tripp Isenhour killed wasn't fit to survive. It's as simple as that.
I'm not condoning Isenhour's actions. He's a small man who probably plucked wings off flies as a kid, assuming he was willing to dirty his precious little spoiled fingers with bug innards.
But the Humane Society or PETA or whoever's calling for action against Isenhour needs to kindly hop off its high horse and find a more suitable target than a pro golfer who never in a million years thought he was actually going to hit a bird with a golf ball. The PGA Tour's slogan is "these guys are good," but nobody's that good.
And no animal should be that dumb. Projectiles flying past its head, the bird not only stays in range -- but moves closer? That bird's an idiot.
No wonder that species of hawk is protected. With instincts like that, extinction is in its future.