Gundersen et al. (2001, Source-sink dynamics: how sinks affect demography of sources. Ecol. Lett., 4, 14–21.) suggested that sinks can severely affect the demography of populations in source habitats. We propose this is a common result when animals lack cues associated with reduced fitness inside sinks 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 habitat choice is a key process underlying source–sink dynamics.