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Coyote Vocal Communication and Its Application to the Selective Management of Problem Individuals By Brian Reid Mitchell B.A. (Brown University) 1994 A dissertation submitted in partial satisfaction of the requirements for the degree of Doctor of Philosophy in Environmental Science, Policy and Management in the GRADUATE DIVISION of the UNIVERSITY OF CALIFORNIA, BERKELEY Committee in charge: Professor Reginald H. Barrett, Chair Professor Steven R. Beissinger Professor Eileen A. Lacey Spring 2004 The dissertation of Brian Reid Mitchell is approved: Chair Date Date Date University of California, Berkeley Spring 2004 Coyote Vocal Communication and Its Application to the Selective Management of Problem Individuals Copyright 2004 By Brian Reid Mitchell 1 Abstract Coyote Vocal Communication and Its Application to the Selective Management of Problem Individuals By Brian Reid Mitchell Doctor of Philosophy in Environmental Science, Policy and Management University of California, Berkeley Professor Reginald H. Barrett, Chair Livestock depredation by coyotes severely affects ranchers, and the existing evidence implicates breeding coyotes in the majority of livestock losses. Management approaches that target these problem individuals will be the most effective way to reduce livestock losses. This dissertation examines coyote long-range vocal communication and the likely usefulness of recorded vocalizations for selective coyote control. The information content of barks and howls is important because coyotes may recognize vocalizing individuals. This could cause coyotes to respond differently to playbacks depending on the individuals used. It is also important to understand how vocal characteristics change over biologically relevant distances, since these changes provide insights into the practical communicative significance of long-range vocalizations. I investigated whether coyote barks and howls were individually distinctive using 293 barks and 280 howls from 7 coyotes. Barks and howls were individually specific: discriminant analysis correctly classified the barks of 5 coyotes 69% of the time, and the howls of 6 coyotes 79% of the time. Howl characteristics did 2 not degrade with distance, and discriminant analysis was 75% accurate at assigning howls recorded at multiple distances to 6 individuals. Bark characteristics were unstable with distance and it is unlikely that barks could be used for individual recognition. Howls and barks probably serve separate functions: howls are optimized to convey information, while barks are suitable for attracting attention and for facilitating distance estimation. Effective playbacks should incorporate both types of vocalization so that the complementary information they contain is available to listeners. A year-long experiment investigated the selectivity and efficacy of a variety of acoustic stimuli for calling coyotes. Transients rarely responded vocally, and territorial coyotes commonly responded to group coyote vocalizations. During optimal conditions, vocal response rates were over 55% for territorial males, 42% for alpha females, 11% for beta females, and below 4% for transients. Territorial coyotes were more likely to approach playbacks than transients, and coyotes more readily approached group howls than other playback types. When conditions were optimal, approach response rates were 47% for alphas, 49% for betas, and 27% for transients. These results suggest that playbacks can be used for selective coyote control. Chair Date i TABLE OF CONTENTS Table of Contents................................................................................................................. i List of Tables .....................................................................................................................iii List of Figures..................................................................................................................... v Acknowledgments............................................................................................................. vii Chapter 1. Coyote Depredation Management: Current Methods and Research Needs..... 1 Coyote Depredation on Livestock ................................................................................ 2 Not All Coyotes Kill Sheep .......................................................................................... 4 Nonlethal Depredation Management ............................................................................ 7 Lethal Coyote Control: Population Reduction............................................................ 10 Lethal Selective Control ............................................................................................. 13 The Future of Coyote Depradation Management Research........................................ 16 Improved Depredation Management Techniques................................................. 17 Outline of the Dissertation.................................................................................... 21 Chapter 2. Information Content of Coyote Long-Range Vocalizations: Individual Differences in Barks and Howls ....................................................................................... 22 Coyote Long-Range Vocalizations....................................................................... 23 Signature Vocalizations or Individual Voice Characteristics? ............................. 24 Individual Differences in Animal Vocalizations .................................................. 25 Methods....................................................................................................................... 26 Recording and Sound Processing Procedures....................................................... 26 Bark Measurements and Variables ....................................................................... 29 Howl Measurements and Variables ...................................................................... 32 Discriminant Analysis........................................................................................... 34 Results......................................................................................................................... 37 Bark Analyses ....................................................................................................... 37 Howl Analyses...................................................................................................... 39 Discussion................................................................................................................... 41 Information Content of Animal Vocalizations ..................................................... 41 Individually Specific Cues in Coyote Vocalizations ............................................ 42 Do Coyotes Use Multivariate Statistics? .............................................................. 44 Chapter 3. Information Content of Coyote Long-Range Vocalizations: Transmission of Individually Specific Vocal Cues ..................................................................................... 56 Methods....................................................................................................................... 58 Recording and Sound Processing Procedures....................................................... 58 Bark Measurements and Variables ....................................................................... 61 Howl Measurements and Variables ...................................................................... 62 Statistical Analyses ............................................................................................... 64 Results......................................................................................................................... 66 Bark Analyses ....................................................................................................... 66 Howl Analyses...................................................................................................... 68 Discussion................................................................................................................... 71 Effects of Sound Processing and Playback........................................................... 71 Barks are Suitable for Distance Estimation .......................................................... 74 Howls Reliably Transmit Information.................................................................. 75 ii Improving Playback Methods............................................................................... 76 Chapter 4. The Potential Utility of Audio Playback for Selective Coyote Control......... 89 Coyote Depredation Management ........................................................................ 90 Coyote Responses to Playback ............................................................................. 92 Methods....................................................................................................................... 96 Study Site.............................................................................................................. 96 Coyote Capture and Processing Procedures ......................................................... 96 Pack Membership and Social Status..................................................................... 98 Playback Trials.................................................................................................... 100 Data Analysis.....................................................................................................

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