Species recognition of song by female red-winged blackbirds

The ability of female red-winged blackbirds, Agelaius phoeniceus, to discriminate between normal songs of local, conspecific males and altered or foreign songs was tested. Females were tested using the solicitation display assay, in which captive females are first treated with oestradiol and then exposed to playback. The number of copulation solicitation displays was the sole response measure. Females responded more strongly to full songs than to songs with all introductory notes removed in tests using nine pairs of stimuli. Females did not discriminate between normal songs and the same songs divided into three parts and reassembled in shuffled orders. Subjects drawn from a Pennsylvania population displayed more in response to local songs than songs recorded in California. Pennsylvania females also responded more strongly to trill portions of Pennsylvania songs than to trill portions of California songs. Overall, the results are compatible with the hypothesis that female red-winged blackbirds are more discriminating than males in species recognition, attending to more acoustic cues than do males.