Killer Whale Discrete Pulsed Call Variation

TitleKiller Whale Discrete Pulsed Call Variation
Publication TypeJournal Abstract
AuthorsGrebner, DM, Bradley, DL, Capone, DE, Parks, S, Miksis-Olds, J, Ford, JKB
JournalJournal of the Acoustical Society of America
KeywordsCall Variation, Killer Whale

Animals can increase and diversify vocal complexity and call content by altering internal features within a call. The Northern Resident orca pods, residing off British Columbia, each have their own dialect of structurally discrete and highly stable pulsed calls. The objective of this study is to determine if there are distinctive internal acoustic features within the defined envelope of a single discrete pulsed call (N04) which could potentially relay the signaler’s behavioral circumstance. Orca discrete pulsed calls are highly complex with varying time‐frequency slopes and multiple sidebands. This analysis began with the parsing of the N04 call into different subtypes based on distinctive changes in time‐frequency slopes found in the call spectrograms. Call subtypes were verified using discriminant analysis, and changes in slope trends (ascending, descending, or constant frequency) at designated locations along the calls were compared. Variations in slopes were found between subtypes predominantly in the calls’ front and terminal regions. Clear and reliable acoustic cues within a discrete pulsed call could not only provide receivers with the physical location and group affiliation of the signaler but also would alert receivers to the signaler’s behavioral state or prey catch which would be vital information for a prey‐sharing species.

Refereed DesignationRefereed