John L. Bower
Bioacoust. Res. Program, Cornell Lab. of Ornithol., 159 Sapsucker Woods Rd., Ithaca, NY 14850
A passive sparse acoustic array of eight microphones was used to characterize the patterns of acoustic interactions of territorial song sparrows. The rectangular array was placed in a four hectare open field (near Ithaca, New York) that contained 11 song sparrow territories. Recordings were made approximately every 3 days from early April, when male song sparrows arrived back from their wintering grounds, through July, when the breeding season ended. Computer analysis of field recordings showed that the array was able to capture vocalizations of all 11 territorial males in the field, and that these vocalizing males could be accurately located. Data were taken during three critical periods of the breeding season: (1) territory establishment, (2) settlement of territories by females, and (3) nesting. For each period, the timing of song, inter-song intervals, and song-type matching were discerned for males. Patterns of acoustic interactions recorded during periods of visually observed male--male conflict were also investigated. These patterns were used to evaluate several hypotheses that seek to explain the function of acoustic interactions in song sparrows.