While the wily coyote reigns as top dog in much of the
US, it leads a nervous existence wherever it coexists
with its larger
relative, the wolf, according to a new study from the Wildlife
Conservation Society. In fact, coyote
densities are more than 30
percent lower in areas that they share with wolves.
The paper, which appeared recently in the Journal of Animal Ecology,
details the results of a study examining the effects of wolves on the
distribution and abundance of coyotes in those areas, Science Daily
said.
“The study tests the hitherto unproven hypothesis that wolves limit the
range and numbers of coyotes in places where the two species compete
with one another,“ said Dr. Kim Murray Berger, a WCS researcher and
lead author of the study. “In this instance, the findings do support
the theory, but coyotes can hold their own against wolves by living in
packs.“
Working in Grand Teton National Park in the southern Greater
Yellowstone Ecosystem, researchers followed radio-collared coyotes at
wolf-abundant and wolf-free locations. They found that while coyotes
remained the numerically dominant predator in locations where wolves
exist, the densities of coyotes was substantially lower in areas
containing both canid species. Specifically, coyote densities were 33
percent lower in wolf-abundant sites in the Tetons. Similarly, coyote
densities declined 39 percent in Yellowstone National Park after wolves
were recently reintroduced there.
In terms of direct mortality, actual predation of wolves on coyotes was
low, accounting for some 16 percent of the radio-collared animals. Also
there was a clear indication that, with coyotes, there’s safety in
numbers;
transient coyotes without packs were more likely to fall prey
to wolves, with 56 percent of transient coyote mortality being
attributable to wolves. Also, transient coyotes in wolf-abundant sites
were 117 percent more likely to leave an area frequented by wolves.
A bigger threat to coyotes than wolves is humans, with 29 percent of the mortality in the study animals being human-related.