THE RESPONSE OF MALE AND FEMALE SONG SPARROWS TO GEOGRAPHIC-VARIATIONIN SONG

We tested female and male Song Sparrows (Melospiza melodia) from a Pen nsylvania site for discrimination between local songs and foreign song s recorded in New York. In Experiments 1 and 2 we measured the copulat ory response of female Song Sparrows to playback of local and foreign songs. In Experiment 3 we measured the aggressive response of territor ial males to playback. We used mean responses per subject as sample po ints in the statistical analysis in Experiment 1, but to avoid pseudor eplication we designed Experiments 2 and 3 with sufficient numbers of exemplars of local and foreign songs to use mean responses per exempla r as sample points. Responses in all three experiments were significan tly stronger for local than for foreign songs. Song Sparrow songs show a great deal of variation within locales, and a pattern of gradual an d subtle geographic change, so it is not obvious how or why our subjec ts performed the discrimination.