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.