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FIGURE 10.14. Examples of the four most common blue whale call types (A-D)
recorded off the west coast of North America are shown as spectrograms. (A)
Sequence of type "A" and "B" calls recorded on a sonobuoy array in the Santa
Barbara channel, California, the loudest "A"-"B" series is believed to be produced
by a single animal, interspersed with some short downsweep "D" calls produced by
a second animal. Weaker calls can be seen in the background from another animal.
The spectrogram was computed with 1s FFT length, 97% overlap, and a Hanning
window. Frequency response is boosted 1.5 dB/octave above 10 Hz.
See text for details on parts Band C.