Table 1 Differences in Song features

a. Analysis using all retrieved songs (n = 149)
Variable Statistic result Neotropical (n = 71) Nearctic (n = 78)
PCA F = 261.4; p < 0.001 NA NA
Number of notes H (2) = 13.916; p < 0.001 7.75 ± 2.07 10.64 ± 2.59
Number of notes per second H (2) = 0.8086; p = 0.3685 6.83 ± 2.8 7.30 ± 1.99
Song length H (2) = 7.1654; p < 0.05 1.23 ± 0.35 1.54 ± 0.48
Time between notes H (2) = 12.197; p < 0.001 0.62 ± 0.22 1.03 ± 0.53
Highest frequency H (2) = 16.098; p < 0.001 7310 ± 441.17 6725 ± 448.56
Lowest frequency H (2) = 28.251; p < 0.001 4230 ± 479.14 3250 ± 288.68
b. Analysis using one song per record (n = 48)
Variable Statistic result Neotropical (n = 20) Nearctic (n = 28)
PCA F = 38.86; p < 0.001 NA NA
Number of notes H (2) = 49.433; p < 0.001 7.93 ± 2.34 11.36 ± 2.59
Number of notes per second H (2) = 11.868; p < 0.001 6.35 ± 2.18 7.49 ± 1.66
Song length H (2) = 18.999;. p < 0.001 1.31 ± 0.36 1.57 ± 0.41
Time between notes H (2) = 52.162; p < 0.001 0.53 ± 0.23 1.00 ± 0.42
Highest frequency H (2) = 65.335; p < 0.001 7443.66 ± 365.57 6744.60 ± 466.45
Lowest frequency H (2) = 94.058; p < 0.001 4245.07 ± 332.86 3256.76 ± 326.49
1. The data are shown as mean ± standard deviation. (a) Difference in the analysis using all retrieved songs. (b) Differences in the analysis using one song per record