Effects on white-tailed deer following eastern coyote colonization

The expansion or recovery of predators can affect local prey populations. Since the 1940s, coyotes (Canis latrans) have expanded into eastern North America where they are now the largest predator and prey on white-tailed deer (Odocoileus virginianus). However, their effect on deer populations remains controversial. We tested the hypothesis that coyotes, as a novel predator, would affect deer population dynamics across large spatial scales, and the strongest effects would occur after a time lag following initial coyote colonization that allows for the predator populations to grow. We evaluated deer population trends from 1981 to 2014 in 384 counties of 6 eastern states in the United States with linear mixed models. We included deer harvest data as a proxy for deer relative abundance, years since coyote arrival in a county as a proxy of coyote abundance, and landscape and climate covariates to account for environmental effects. Overall, deer populations in all states experienced positive population growth following coyote arrival. Time since coyote arrival was not a significant predictor in any deer population models and our results indicate that coyotes are not controlling deer populations at a large spatial scale in eastern North America.