Evidence against the continuity-versatility relationship in bird song

A relationship between the continuity and versatility with which birds sing appears to be accepted in the literature. Several authors have predicted such a trend on the basis that relatively continuous singing would lead to the listener's habituation, unless successive songs were different. In this paper a series of tests involving both within-and between-species comparisons of New World warblers (Parulinae) were performed, but these tests produced no consistent evidence for the predicted relationship. Furthermore, re-analyses of other work showed that some previous claims of support are unreliable. Thus these new data, and the re-examination of previous work, suggest that a relationship between continuity and versatility should be considered neither general nor predictable.