Summary: | Progress Code: completed Statement: Fourteen standard audio cassettes of in-air calls were recorded using a sound level meter and Sony WM-D6 cassette recorder. Using a low fidelity hydrophone, underwater recordings were obtained on 16 days. A parallel set of underwater recordings were made using a variety of Bruel and Kjaer hydrophones and preamplifiers and a Uher 4400 reel-to-reel tape recorder. All recordings were made near a single group of 34 mother-pup pairs. At least 2 adult males were in the area. The seals that were on the ice were approached to 1-2 m and were recorded if they vocalised (many did not). The underwater recordings were made at three locations within and near the group of seals on the ice. The underwater and in-air recordings were used to derive a technique to classify the call types. The in-air recordings demonstrated that both males and females vocalise and often a single seal will string up to 6 call types together in a variety of orders. No 'Trills' were heard by males or females on the ice. The seals lengthened the duration of multiple-element calls when they were 'interrupted' by another calling seal. This suggests that the seals are listening for the calls of conspecifics while they themselves are calling. A pilot project indicated that almost none of the calls are completely masked by other calling seals. The recordings are being used (in association with recordings obtained in later years) to address other aspects of Weddell seal vocal communication. See the link below for public details on this project.
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