a, Repertoire and proportions of different types of bouts. PTP: tonal segments both preceded and followed by trains of pulses; PT: tonal segments preceded by trains of pulses; TP: tonal segments followed by trains of pulses; P/T: isolated pulse trains or tonal segments. b, Modulation of the fundamental frequency of tonal segments (n = 10, means ± s.e.); mean individual values were obtained from the means of each bout. Frequencies of the three portions (see
Fig. 3a
for abbreviations) were significantly different (Friedman ANOVA by ranks, df = 2, Chi Square = 10.40, p<0.01). Frequency of C and F significantly differed from I (Wilcoxon Matched Pairs test, p<0.05), but not one from each other (p = 0.20).