Predation risk increases intraspecific heterogeneity in white-tailed deer diel activity patterns

Abstract

Prey species often mitigate predation risk through alteration of spatiotemporal diel activity patterns whereby prey access high-quality resources in risky areas during predator downtimes. However, dominance hierarchies exist in some prey species, and temporal partitioning is a mechanism thought to reduce aggressive intraspecific interactions. How demographic-specific responses to predation risk influence intraspecific temporal partitioning in prey are largely unknown and could be key to understanding the effects of predators on intraspecific interactions in prey. To assess the effects of predation risk on intraspecific interactions in white-tailed deer (Odocoileus virginianus), we monitored deer diel activity during the fawning season in four pairs of predator exclusion and control plots (~40 ha) from 2015 to 2018 using 16 camera traps. We examined the effect of predation risk on diel activity of males, females, and nursery groups by comparing the within-group coefficient of activity overlap (d̂) across predator exclusion and control plots. We then examined within-treatment activity overlap between groups in the predator exclosure and control plots. All groups maintained different diel activity patterns in safe and risky areas. Unconstrained by predation risk, all groups behaved more similarly, and interspecific group overlap was greater in the predator exclusion plots than control plots. Male-nursery group overlap exhibited the strongest treatment effect, increasing 24% in predator exclusion plots (d̂ = 0.91, confidence interval [CI]: 0.87–0.95) relative to control plots (d̂ = 0.67, CI: 0.57–0.76). Our results suggest predators increase heterogeneity in prey behavior and may be important drivers of behavioral processes, such as temporal partitioning, that minimize antagonistic intraspecific interactions of prey.

White‐tailed deer exploit temporal refuge from multi‐predator and human risks on roads

“…We identified divergent diel activity patterns among deer age and sex classes, as found previously (Crawford et al, 2021 ; Higdon et al, 2019 ; Lashley et al, 2014 ; Murphy et al, 2021 ). Deer fawns in the southeastern United States increased diurnal activity compared with adult deer to avoid their primary predator, coyotes (Crawford et al, 2021 , Higdon et al, 2019 ).…”

“…We identified divergent diel activity patterns among deer age and sex classes, as found previously (Crawford et al, 2021 ; Higdon et al, 2019 ; Lashley et al, 2014 ; Murphy et al, 2021 ). Deer fawns in the southeastern United States increased diurnal activity compared with adult deer to avoid their primary predator, coyotes (Crawford et al, 2021 , Higdon et al, 2019 ). Deer exposed to wolf urine in a wolf‐free environment become more diurnal (Palmer et al, 2021 ), suggesting that reduced nocturnal behavior is a general deer reaction to predation risk and not a response to nocturnal activity from sympatric predators.…”

“…From the camera survey, we considered all images of a single species within 15 minutes of separation at a site as a single detection. We classified deer demographic groups following Crawford et al (2021) and Higdon et al (2019), where any deer detection with at least one fawn present was considered a nursery group, an adult female detection with no fawns observed was classified as an adult female, and an adult male detection with no fawn present was classified as an adult male. We estimated diel activity distributions for deer nursery groups, adult female deer, adult male deer, coyotes, wolves, black bears, bobcats, and humans using a circular kernel density estimator within the Activity package (Rowcliffe, 2019) for program R. We assessed activity overlap () of deer and predators using the compareCkern function (Ridout & Linkie, 2009; Rowcliffe, 2019).…”

“…White‐tailed deer ( Odocoileus virginianus ; hereafter deer) adults and juveniles experience differing predation risks (Chitwood et al, 2015 ) and respond differently to predation risk (Gulsby et al, 2018 ). Demographic variability in diel activity may be an important predator defense for deer, which reduce nocturnal activity of young fawns to reduce their exposure to coyotes ( Canis latrans ; Higdon et al, 2019 , Crawford et al, 2021 ) and when exposed to wolf urine (Palmer et al, 2021 ). However, these studies examined deer temporal responses to a single predator, whereas fawns in most deer populations are killed by multiple predators and humans (Gingery et al, 2018 ).…”

Diel and monthly activity pattern of brown bears and sika deer in the Shiretoko Peninsula, Hokkaido, Japan

“…Brown bears are potential predators of sika deer, and predation risk can alter the diel activity patterns of prey animals. For example, white-tailed deer with a fawn concentrated diel activity during diurnal periods when coyotes (Canis latrans), their major predators, are least active [4].…”