Coyote diet and spatial co-occurrence with caribou

The interplay of predator encounters and anti-predator responses is an integral part of understanding predator-prey interactions and spatial co-occurrence and avoidance can elucidate these interactions. We conducted hard-part dietary analysis of coyotes (Canis latrans Say, 1823) and space use of coyotes and caribou (Rangifer tarandus Gmelin, 1788) to test two competing hypotheses about coyote and caribou predator-prey spatial dynamics using resource selection functions. The high encounter hypothesis predicts that coyotes would maximize encounters with caribou via high spatial co-occurrence, whereas the predator stealth hypothesis predicts that through low spatial co-occurrence with caribou, coyotes act as stealth predators by avoiding habitats that caribou typically select. Our dietary analysis revealed that ~46% of sampled coyote diet is composed of caribou. We found that coyote share space with caribou in lichen-barren habitat in both summer and winter and that coyotes co-occur with caribou in forested habitat during summer, but not winter. Our findings support predictions associated with the high encounter predator hypothesis whereby coyotes and caribou have high spatial co-occurrence promoting caribou in coyote diet.