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Dissertation on coyote vocal communication

Subject: Dissertation on coyote vocal communication
From: Brian Mitchell <>
Date: Fri, 07 May 2004 10:51:38 -0700
<tt>Hello list,</tt><br>
 <tt>My dissertation is now finished, and available online at (currently on the main page, lower-right 
 side, and will eventually be available through the "Theses" link) or</tt><br>
 <tt>TITLE: Coyote Vocal Communication and Its Application to the Selective 
 Management of Problem Individuals</tt><br>
 <tt>ABSTRACT: 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.<br>
         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 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<br>
 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.<br>
         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.</tt><br>
 <pre style="margin: 
 Brian R. Mitchell
 Post-Doctoral Associate
 University of Vermont
 The Rubenstein School of Environment and Natural Resources
 George D. Aiken Center
 81 Carrigan Drive
 Burlington, VT  05405-0088
 (802) 656-2496

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