Fig. 2.

(A) Plot of successive IPIs (gray) and ESDs (green) for one representative flight. (B) Plot showing overlap (pink data-points) or nonoverlap (gray data-points) of ESDs, with consequent pulse–echo ambiguity from one sound to the next for strobe groups (negative vertical-axis values represent overlap.) (C) Plot showing high (HF) and low (LF) frequencies in FM1 for successive sounds from the same flight. When ESDs overlap, frequencies of the first sound are higher and frequencies of the second sound are lower (ΔF). Between the first and the second sound of each strobe group, plots show dependence of FM1 high frequency (HF) (D), FM1 low frequency (LF) (E), FM1 bandwidth (BW) (F), FM1 frequency at peak amplitude (G), relative sound amplitude (H), and sound duration (I) on the amount of ESD overlap. Plots in D–I are labeled with value of correlation coefficient (r), number of sound pairs (N), and significance of correlation (P).