Gundersen et al. (2001, Source-sink dynamics: how sinks affect demography o
f sources. Ecol. Lett., 4, 14-21.) suggested that sinks can severely affect
the demography of populations in source habitats. We propose this is a com
mon result when animals lack cues associated with reduced fitness inside si
nks and consequently select habitat inappropriately. These attractive sinks
can result either from undetected risks of mortality (as in the experiment
of Gundersen et al. 2001) or from undetected poor breeding probabilities (
due to bioaccumulation of pesticides, for instance). Thus, individual habit
at choice is a key process underlying source-sink dynamics.