This article is from the Birds FAQ, by Lanny Chambers with numerous contributions by others.
Christopher Leahy, in _The Birdwatcher's Companion_ (New York: Hill &
Wang, 1982), writes: "If you stop feeding, the healthy members of your
clientele will resort to wild food sources (or your neighbor's feeder)
without hesitation. Only those which need a 'crutch' to survive are
likely to fall prey to real life."