Different outcomes of synergy between song production and song perception in the same subspecies (Molothrus ater ater).

Here we report data requiring a reinterpretation of published results on the female cowbird's (Molothrus ater ater) ability to identify male song (King, A. P., and West, M. J. (1983). Female perception of cowbird song: A closed developmental program. Dev. Psychobiol., 16:335-342). Previously we stated that naive females, given extensive social experience with males from a distant cowbird subspecies, showed the same degree of preference for native song as did naive females reared with local males: extensive experience with another subspecies produced no evidence of postnatal modifiability. The procedure used to probe for modifiability did not, however, expose the different groups of females to comparable levels of stimulation because the females differentially affected the behavior of their male companions. We must therefore amend our conclusion about the modifiability of females. In addition, we report data on populational differences within the M.a. ater subspecies in the female's ability to influence heterosubspecific males, but data that are consistent with the more general pattern of synergistic effects during song development.