Coyote vocal communication and its application to the selective management of problem individuals

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 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.