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OVERVIEW
My Ph.D.
research was primarily
supported by the United States Department of Agriculture, Animal and
Plant
Health Inspection Service, Wildlife Services, National Wildlife
Research Center
(NWRC).
The main mission of
this agency
is to conduct research that helps solve conflicts between human
interests and
wildlife.
The California Field
Station
of the NWRC was focused on basic research aimed at getting a better
understanding of coyote behavior, with the goal of developing more
selective
and effective methods of reducing coyote depredation of livestock. Previous
graduate students at the
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COYOTE
BIOACOUSTICS
My
research began with a trip to
the NWRC’s field station in
By analyzing spectrograms of howls and barks, I was able to determine that both of these vocalizations do indeed contain individually specific information. Because of the tremendous advantage of being able to determine individual identities, I presume that coyotes use the information in barks to identify individuals they are familiar with. Another interesting aspect of coyote barks and howls is that howls stably convey information for distances of at least one kilometer. Barks, on the other hand, rapidly attenuated and did not appear suitable for transmitting information. Barks likely serve other purposes, such as attracting information and providing information that listeners could use to estimate distance to the barking animal. |
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PLAYBACK EXPERIMENTS
I conducted two years of playback experiments on radio collared coyotes at the Dye Creek Preserve, a property managed by The Nature Conservancy in Coyotes
could respond by
vocalizing
or by approaching a playback.
Vocal
responses were most likely to coyote group vocalizations when there was
low
wind.
Vocal responses were
also more
common just before dawn and during periods when the moon was up and
bright.
The vocally responding
animals
were almost exclusively territorial alphas and betas; transients rarely
vocalized.
Approach
responses were most
likely
to playbacks of group vocalizations (although human imitations of
coyotes
generated similar levels of approach responses). Approaches
were most common when playbacks
were within the responding animal’s home range, during the
first
half of the
year, and at or before sunrise.
Territorial
coyotes were twice as likely to respond as
transients.
The results from the first year of playback studies strongly support the use of playbacks to locate or selectively attract territorial coyotes. Coyote control actions based on the use of coyote vocalizations may be more selective than many existing techniques… but this needs to be tested with rigorous operational experiments. |
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OTHER COYOTE RESEARCH
Any large project generates a number of spin-offs, and mine was no exception. Other coyote-related projects that I have been working on include a genetic analysis of the relatedness of individuals in my study population, a mark-recapture study using DNA found in scat, and a pilot study with GPS collars investigating how coyotes respond to human presence. The relatedness analysis is not yet complete, but preliminary findings indicate some evidence of infidelity among alpha pairs. In addition, there is evidence of a tendency for coyotes to inherit their parents’ territory or settle in adjacent territories. This could potentially lead to a situation where extended families benefit from living next to each other through reduced territorial aggression. The scat DNA study is ongoing; Christen Williams of the NWRC is analyzing the samples, and we will conduct a mark-recapture analysis of the data to determine the size of the Dye Creek population. Estimating the density of carnivores is particularly difficult, so we hope that scat DNA provides a cost effective tool for tracking carnivore numbers. The advent of GPS collars small enough to be worn by coyotes provided me with an opportunity to look at how coyotes react to human presence. Several coyotes were fit with GPS collars that recorded their exact location every 15 minutes. While these coyotes were collared, my field crew and I recorded our locations as we traveled and worked on the study site; our activities were the majority of human activities on the preserve. I hope to analyze this data to better understand how coyotes react to research activities. |
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