| Summary: | Thesis (M.Sc.)--Memorial University of Newfoundland, 1985. Psychology Bibliography: leaves 102-108. Vocalizations of free-ranging North Atlantic pilot whales were studied in different behavioral and environmental contexts to gain insight into the function and biological significance of different sound types. Pilot whales in Conception Bay, Newfoundland, were followed for a period of a week, night and day. Concurrent visual and acoustic recordings were made, and correlations were examined between the different acoustic, behavioral, and environmental variables. Whistles were categorized into 7 types based on the aural impression of the whistles' contour. -- Simple whistles (with no frequency inflections) were more common than complex whistles (more than 2 frequency inflections), which were rare. Simple whistles were heard when whales were milling, a restful behavior type which occurred over shallower water. In contrast, during surface active-behavior, energetic coordinated behavior thought to be feeding, many sound types, especially complex whistles and pulsed sounds, increased in number. More clicking (thought to function in echolocation) was also heard. Greater numbers of most whistle types were produced when whales were spread over a larger area and when more subgroups were present. During conditions of high wind speed and wave height (which produced much background noise) groups were larger and in tight formation with fewer surrounding subgroups present. Whales moved in a less unified manner when the group was larger and scattered over a greater area. -- It was concluded that in pilot whales, complexity of sound and complexity of behavior (requiring a high level of coordination) were related. Vocalizations were thought to play an integral part in maintaining contact between group members and coordinating movements of the herd.
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