I never really thought about it before, but maybe that explains why we always had tomato hornworms at our old houses (not that many trees = not that many birds), but seldom do here at our present house (an abundance of trees = lots of hungry birds).
(We can't put out birdseed to feed them; the neighborhood also has an abundance of rats. Fortunately we don't seem to need to. The birds do fine foraging seed heads and fruit on various trees, shrubs, and plants (both ours and in the neighborhood), and some of them also take care of quite a few snails. I wish more of them went after the various flies here, though!)
