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The table below summarizes data from 10 passbooks when orcas made sounds in front of the OrcaSound hydrophone array.
7 of 10 passbys had both calls and echolocation clicks. Passby 7 (6/25) has
a much larger standard deviation from the echo click average track than from
the call average track. The calls in passby 9 are even more compact than in
the 6/25 passby shown in the figure above. Generally the echolocations are
more spread out in relation to the echo track than are the calls with respect
to the call track – with passby 4 being the only exception.
When the orcas vocalize, they may make many sounds over a considerable time period, here ranging up to a half-an-hour or they may cease vocalizing after just a few minutes. In this table, we see the length of the passby in minutes, the number of calls and echolocation clicks that were localized, the average separation between the moving location of the echolocation clicks and the calls, when both are intermixed. In no case does it appear that the average location of the echolocation clicks is coincident with the average location of the calls. On the two occaisons when only echos were observed, these echos ranged over a much larger domain than in any of the cases when both echolocation clicks and calls were localized. This result follows from the large values in the "Standard Deviation from Path" column above for passbys 1 and 2. With only one exception, the echolocation clicks come from a broader domain that do the calls that the clicks are interspersed with.