Table 1 Descriptions of 30 acoustic variables. Noise-related variables (P < 0.05) are shown into bold italics.
Variable | Description (unit) |
|---|---|
Time-based variables | |
DUR | Duration of the call (s) |
DISTTOMAX | Temporal distance from start to the location of the maximum amplitude (s) |
Frequency-based variables | |
PFSTART | At start of the call, peak frequency (the frequency of the maximum amplitude) is measured (Hz) |
Q1START | At start of the call, the quartile 25% frequency (below this frequency is 25% of the total energy) is measured (Hz) |
Q2START | At start of the call, the quartile 50% frequency (below this frequency is 50% of the total energy) is measured (Hz) |
Q3START | At start of the call, the quartile 75% frequency (below this frequency is 75% of the total energy) is measured (Hz) |
PFEND | At end of the call, peak frequency is measured (Hz) |
Q1END | At end of the call, the quartile 25% frequency is measured (Hz) |
Q2END | At end of the call, the quartile 50% frequency is measured (Hz) |
Q3END | At end of the call, the quartile 75% frequency is measured (Hz) |
PFMAXA | At the location of the maximum amplitude of the call, peak frequency is measured (Hz) |
Q1MAXA | At the location of the maximum amplitude of the call, the quartile 25% frequency is measured (Hz) |
Q2MAXA | At the location of the maximum amplitude of the call, the quartile 50% frequency is measured (Hz) |
Q3MAXA | At the location of the maximum amplitude of the call, the quartile 75% frequency is measured (Hz) |
PFMIN | The minimum frequency of the call; the lowest peak frequency of the call (Hz) |
Q1MIN | The minimum quartile 25% frequency of the call (Hz) |
Q2MIN | The minimum quartile 50% frequency of the call (Hz) |
Q3MIN | The minimum quartile 75% frequency of the call (Hz) |
PFMAX | The maximum frequency of the call (Hz); the highest peak frequency of the call |
Q1MAX | The maximum quartile 25% frequency of the call (Hz) |
Q2MAX | The maximum quartile 50% frequency of the call (Hz) |
Q3MAX | The maximum quartile 75% frequency of the call (Hz) |
PFMEAN | The mean frequency of the call (Hz); the mean peak frequency of the call |
Q1MEAN | The mean quartile 25% frequency of the call (Hz) |
Q2MEAN | The mean quartile 50% frequency of the call (Hz) |
Q3MEAN | The mean quartile 75% frequency of the call (Hz) |
Frequency-modulation-based variables | |
PFSTDDEV | The relative standard deviation (= standard deviation/mean value) of the peak frequency within the call; frequency modulation within the call |
Q1STDDEV | The relative standard deviation (= standard deviation/mean value) of the quartile 25% frequency within the call |
Q2STDDEV | The relative standard deviation (= standard deviation/mean value) of the quartile 50% frequency within the call |
Q3STDDEV | The relative standard deviation (= standard deviation/mean value) of the quartile 75% frequency within the call |
