SONG CATEGORIES AND THEIR FUNCTIONS IN THE FIELD SPARROW (SPIZELLA-PUSILLA)

Two song categories, distinguished by their acoustic structure, contextual usage, and potency in provoking responses from territorial males, are found in repertoires of individual male Field Sparrows (Spizella pusilla). Simple songs are sung spontaneously throughout the day and in long-distance countersinging by territorial males. Complex songs are sung most frequently during the dawn chorus and during territorial boundary chases. Most males sing one simple and one complex song type. Males responded more strongly to playback of complex songs than to simple songs. Our experiment supports the hypothesis that male songbirds respond differently to songs that are sung in different contexts.