They always mean beautiful things like hummingbirds. I always reply by saying that I think of a little child in East Africa with a worm burrowing through his eyeball. The worm cannot live in any other way, except by burrowing through eyeballs. I find that hard to reconcile with the notion of a divine and benevolent creator.
(Responding to religious viewers who criticize him for not crediting God in his nature episodes)