Spectrograms of killer whale call types with high frequency components as indicated by the arrows (right graphs) and without high frequency components (left graphs).
Box plots showing median (dark line), 25th–75th percentile (box) and 5th-95th percentile (whiskers) of source levels (shaded, left side y axis) and paired noise levels (unshaded, right side y axis) for each call type.
Call source level as a function of background noise level plotted for each call type. The call type is shown in upper left corner along with the regression equation and R 2 values; 95% confidence intervals are shown as dashed lines.
Pod presence by number of recording days.
Summary of southern resident killer whale call types reported in this study, including those with a high frequency component (HFC). Sample size (N) and linear regression results of source level by noise level for each call type and pairwise comparisons results of source levels between call types based on the Tukey HSD test; unadjusted mean differences are shown in parentheses and based on ANOVA (call type was a single factor), adjusted mean differences are based on ANCOVA with noise level as a covariate; significant differences (P < 0.05) are shown in bold, with the exception of S1 vs S19 in which P = 0.05 (indicated by *), NS = not significant.
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