Dear colleagues,
I would like to draw your attention to a paper just published in Animal
Behaviour (Vol 71: 79-91) on stereotyped whistles in wild killer whales. The
paper can be directly accessed via the journal's web page. For further
inquiries / questions, please contact me directly
Best,
Frank
Stability and group specificity of stereotyped whistles in resident killer
whales, Orcinus orca, off British Columbia
Rüdiger Riesch 1, John K.B. Ford 2, and Frank Thomsen 1
1 Biozentrum Grindel, Universität Hamburg, Germany
2 Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, Canada
Resident killer whales off British Columbia form four acoustically distinct
clans, each with a unique dialect of discrete pulsed calls. Three clans belong
to the northern and one to the southern community. Resident killer whales also
produce tonal whistles, which play an important role in close-range
communication within the northern community. However, there has been no
comparative analysis of repertoires of whistles across clans. We investigated
the structural characteristics, stability and group specificity of whistles in
resident killer whales off British Columbia. Acoustic recordings and
behavioural observations were made between 1978 and 2003. Whistles were
classified spectrographically and additional observers were used to confirm our
classification. Whistles were compared across clans using discriminant function
analysis. We found 11 types of stereotyped whistles in the northern and four in
the southern community with some of the whistle types being stable over at le
ast 13 years. In northern residents, 10 of the 11 whistle types were
structurally identical in two of the three acoustic clans, whereas the whistle
types of southern residents differed clearly from those of the northern
residents. Our study shows that killer whales that have no overlap in their
call repertoire use essentially the same set of stereotyped whistles. Shared
stereotyped whistles might provide a community-level means of recognition that
facilitates association and affiliation of members of different clans, which
otherwise use distinct signals. We further suggest that vocal learning between
groups plays an important role in the transmission of whistle types.
-- Dr. Frank Thomsen biologisch-landschaftsökologische Arbeitsgemeinschaft
(biola) & Lehrbeauftragter Biozentrum Grindel Universität Hamburg
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