Diel and seasonal patterns of variation in the singing behaviour of Savannah Sparrows ( Passerculus sandwichensis )

Background The vocalizations of birds are dynamic traits that often vary in output with time of day and time of year. By quantifying patterns of diel and seasonal variation in vocal output, we can gain insight into the ecology and evolution of birds and the function of their vocalizations. In this investigation, we quantified diel and seasonal variation in song output by studying a breeding population of Savannah Sparrows (Passerculus sandwichensis).