Data from: Predicting multi-predator risk to elk (Cervus canadensis) in summer using predator scats

1. There is growing evidence that prey perceive the risk of predation and
alter their behaviour in response, resulting in changes in spatial
distribution and potential fitness consequences. Previous approaches to
mapping predation risk across a landscape quantify predator space use to
estimate potential predator-prey encounters, yet this approach does not
account for successful predator attack resulting in prey mortality. An
exception is a prey kill site that reflects an encounter resulting in
mortality, but obtaining information on kill sites is expensive and
requires time to accumulate adequate sample sizes. 2. We illustrate an
alternative approach using predator scat locations and their contents to
quantify spatial predation risk for elk (Cervus canadensis) from multiple
predators in the Rocky Mountains of Alberta, Canada. We surveyed over
1300km to detect scats of bears (Ursus arctos/U. americanus), cougars
(Puma concolor), coyotes (Canis latrans), and wolves (C. lupus). To derive
spatial predation risk, we combined predictions of scat-based resource
selection functions (RSFs) weighted by predator abundance with predictions
that a predator-specific scat in a location contained elk. We evaluated
the scat-based predictions of predation risk by correlating them to
predictions based on elk kill sites. We also compared scat-based predation
risk on summer ranges of elk following three migratory tactics for
consistency with telemetry-based metrics of predation risk and
cause-specific mortality of elk. 3. We found a strong correlation between
the scat-based approach presented here and predation risk predicted by
kill sites and (r = 0.98, P < 0.001). Elk migrating east of the Ya
Ha Tinda winter range were exposed to the highest predation risk from
cougars, resident elk summering on the Ya Ha Tinda winter range were
exposed to the highest predation risk from wolves and coyotes, and elk
migrating west to summer in Banff National Park were exposed to highest
risk of encountering bears, but it was less likely to find elk in bear
scats than in other areas. These patterns were consistent with previous
estimates of spatial risk based on telemetry of collared predators and
recent cause-specific mortality patterns in elk. 4. A scat-based approach
can provide a cost-efficient alternative to kill sites of quantifying
broad-scale, spatial patterns in risk of predation for prey particularly
in multiple predator species systems.