Abstract:
The Coyote (Canis latrans) is one of the most studied species in North America with at least 445 papers on its
diet alone. While this research has yielded excellent reviews of what coyotes eat, it has been inadequate to draw
deeper conclusions because no synthesis to date has considered prey availability. We accounted for prey availability
by investigating the prey selection of coyotes across its distribution using the traditional Jacobs’ index
method, as well as the new iterative preference averaging (IPA) method on scats and biomass. We found that coyotes
selected for Dall’s Sheep (Ovis dalli), White-tailed Deer (Odocoileus virginianus), Eastern Cottontail Rabbit
(Sylvilagus floridanus), and California Vole (Microtus californicus), which yielded a predator-to-preferred prey
mass ratio of 1:2. We also found that coyotes avoided preying on other small mammals, including carnivorans and
arboreal species. There was strong concordance between the traditional and IPA method on scats, but this pattern
was weakened when biomass was considered. General linear models revealed that coyotes preferred to prey upon
larger species that were riskier to hunt, reflecting their ability to hunt in groups, and were least likely to hunt solitary
species. Coyotes increasingly selected Mule Deer (O. hemionus) and Snowshoe Hare (Lepus americanus) at
higher latitudes, whereas Black-tailed Jackrabbit (L. californicus) were increasingly selected toward the tropics.
Mule Deer were increasingly selected at higher coyote densities, while Black-tailed Jackrabbit were increasingly
avoided at higher coyote densities. Coyote predation could constrain the realized niche of prey species at the distributional
limits of the predator through their increased efficiency of predation reflected in increased prey selection
values. These results are integral to improved understandings of Coyote ecology and can inform predictive
analyses allowing for spatial variation, which ultimately will lead to better understandings about the ecological
role of the coyote across different ecosystems.
