| The unusual fall song produced by northern mockingbirds ( Mimus polyglottos) was examined and compared to the breeding season song of the same species. Aspects of song production studied were (1) female reproductive behaviors usually associated with male singing, (2) the amount of time and energy males devoted to song production, (3) the structure of the songs' elements, and (4) responses playback of the songs elicit from conspecifics. It was found that (1) although females appear to respond to song by soliciting copulations and building nests in the breeding season, they do not engage in these behaviors in the fall, (2) paired males devote considerably less time and energy to song production in the fall than during the breeding season, but the same is not true for unpaired males, (3) the structures of breeding season and fall song do not differ from one another, and (4) playbacks of songs of the two seasons do not elicit different responses from conspecifics. It was concluded that for unpaired males, fall song functions to attract potential mates, and for paired males, fall song may also have inter-sexual functions (though territorial defense was not ruled out). The findings that the songs of the two seasons do not differ from one another in terms of structure or of the responses they elicit in conspecifics are at variance with earlier findings. Those findings were, however, obtained from work containing methodological problems that were corrected in this study. |
