Fig 1.
American redstart flight call variants, Hann Window, FFT 256, ovlp = 85%.
See supplementary material for more detailed descriptions. a) Type A, a typical redstart flight call as described in Evans and O'Brien (2002); b) Type G, an acute, convex inflection, followed by a shallow, obtuse inflection and modulated tail; c) Type M, two convex inflections at the beginning and tail of call with a concave inflection in the middle; d)Type S, obtuse, concave inflection in middle of call while tail of call is a lower frequency than the beginning; e)Type V, approximately equal in duration on either side of acute concave inflection.
Table 1.
Number of birds recorded in both age and gender categories.
Fig 2.
2-D Principal Coordinate Analysis (PCoA) plot based on extracted feature measurements showing multivariate homogeneity of group dispersions between all calls (N = 180),with 99% confidence ellipse based on the standard errors of the axis score averages.
Calls from the same sex are plotted in relation to their centroids (M = Male, F = Female). Differences between sexes were shown to be statistically significant (MANOVA; F = 12.46, R2 = 0.059, p < 0.001). Two orthogonal axes summarize the variability in the data set.
Table 2.
Number of calls in each variant class by gender and age of bird.
Fig 3.
2-D Principal Coordinate Analysis (PCoA) plot based on extracted feature measurements showing multivariate homogeneity of group dispersions between all calls (N = 180), with 99% confidence ellipse based on the standard errors of the axis score averages.
Calls from the same variant class are plotted in relation to their centroids. Differences between classes were shown to be statistically significant (MANOVA; F = 4.51, R2 = 0.086, p < 0.001). Two orthogonal axes summarize the variability in the data set. Note: The M centroid is behind the V centroid, but has the large confidence ellipse.
Fig 4.
Similarity matrix generated by calculating random forest distance between quantitative features measured from flight calls.
Birds are labeled by the bird band assigned given to the bird when the recording was made at the Powdermill bird banding station (S4 Table). The individual pixels in the matrix represent the pairwise similarity values between the 180 flight calls, and the dark grid lines between pixels separate the calls from different individuals (N = 36 individuals, with 5 calls from each). Darker pixels indicate higher pairwise similarity.