Testing the Motivation-Structural Rules Hypothesis in Southern Resident Killer Whales Kathryn Scurci Beam Reach Spring 2010

Background 3 pods of Southern resident killer whales (J, K, and L) Different “dialects” in pods 3 types of phonations: Clicks Whistles Pulsed calls Discrete, variable, aberrant S1 and S 4 = common J calls S2 and S19 = common L calls S16 and S17 = common K calls Ford 1991

The Motivation-Structural Rules Hypothesis The harshness or tonality of a sound gives insight regarding the caller’s motivational/emotional state (Morton 1977) Applies to close-contact situations Darwin’s Principle of Antithesis (1872) Evolutionary advantage of unambiguous calls August and Anderson 1987

Harsh, Tonal, and Frequency-Modulated Calls Used in Study S37 (Harsh) S19 (Tonal) V4 (Frequency-Modulated)

Methods Data Sets: Beam Reach 2010 Collected on the Gato Verde during 5 weeks at sea Historical data from Lime Kiln State Park Recordings made by Monika Wieland Behavioral Data taken by Dr. Robert Otis and students Greeting Ceremony video Six minute recording and corresponding video from 2005

Kruskal-Wallis Test (p=0.037) Combined Monika’s data with my data Kruskal-Wallis Test (p=0.037)

(Kruskal-Wallis Test, p=0.015) Trend = there is a significant difference between the occurrence of the three measured call types. By looking at the graphs, it becomes evident that S19 is the “statistically significant” call. (Kruskal-Wallis Test, p=0.015)

Harsh, Tonal, and F-Modulated Call Rates for Greeting Ceremony and Other Data Sets me up for future work. YAHOO! FIX P VALUE ON THIS SLIDE – ASK JASON IF NEED Rates of S37, S19, and V4 were much higher in Greeting Ceremony than in other recordings (Wilcoxon Signed Rank Test, p>0.03)

Conclusions Limitations of study: Future studies: Small sample size Narrow definitions Inconsistent methods of data collection Future studies: Specific acoustic parameters should be used to quantify harshness and tonality Efforts should be made to measure aggressive behavior Conclusions

Acknowledgements I am very grateful to the following individuals and institutions for contributing to the realization of this study: Friday Harbor Labs, University of Washington Dr. Jason Wood Dr. Val Veirs Dr. Scott Veirs Capt. Todd Shuster Ken Balcomb Monika Wieland Dr. Robert Otis Orca Network Libby Whiting, Nora Carlson, and Horace Liang