Assessment of Variability in Delivery of Songs By Territorial Males of the Eastern Field Sparrow, Spizella pusilla pusilla

Abstract

The overall frequency and rate of delivery of song of the Eastern Field Sparrow, Spizella pusilla pusilla, were studied on a site near Boonsboro, in Washington County, Maryland for possible effects by weather conditions, time of day, a neighbor's singing and mating status. The Kolmogorov-Smirnov test was used to compare frequency distributions of between-song intervals at two times of time of day, and those during which a neighbor's song occurred with those during which no neighbor sang. It was discovered that weather conditions and time of day affected the frequency of song, and that the rate of delivery of individuals changed according to time of day and the neighbor's singing. Pairing seemed to reduce singing frequency to near zero, but a few individuals who continued to sing after pairing showed significant differences in their rates of delivery. The direction of shift in interval length was not consistent among the birds, although most individuals showed an increase in the percentage of longer intervals when a neighbor was singing and later in the day.