Song dynamics in bouts. (a) The carrier frequency of sine trains is modulated during song bouts. An example raw song trace is shown below in grey with sine trains shown in blue and the sine carrier frequency, measured in 50 ms bins, is shown as colored points above. Different colors indicate separate bouts of song. (b) Averaged across the entire dataset, the sine carrier frequency tends to increase over the course of a single bout. The frequency of sine trains within a bout was subtracted from the mean frequency of the initial bin of the first sine train. Histograms of the distribution of data at each time point are illustrated as colored plots across time, with a scale bar on the right indicating the log of the sample size. The mean and the standard deviation of the scaled carrier frequency are indicated with bold and thin black lines and the scaled carrier frequency at the beginning of each sine train within a bout is indicated with a red point. (c) The scaled average pulse carrier frequency displays a noisy decreasing trend over the course of a song bout. Colors and symbols as in b. (d) Sine train carrier frequency as a function of recording time for a single individual displays an increase in the mean carrier frequency with time. (e) The correlation coefficients for multiple song parameters as a function of recording time for all individuals for bout duration, sine train duration, pulse train duration, sine carrier frequency, pulse carrier frequency, and inter-pulse interval.