Evaluating predictors of white-tailed deer (Odocoileus virginianus) birth-site selection along an urban-rural gradient

Abstract

Birth-site selection by parous white-tailed deer (Odocoileus virginianus) may affect neonate survival, but factors influencing selection in urbanized areas are poorly understood. Our objectives were to describe deer birth sites in Durham and Orange counties, North Carolina, evaluate landscape features as predictors of selection, and assess whether selection for these predictors varied along an urban-rural gradient. We captured and monitored 95 adult female white-tailed deer from 2022 to 2024. Out of those 95 individuals, we identified birth sites for 61 female deer and determined 5 available sites within each female’s fawn-rearing area, derived from global positioning system (GPS) locations 6-weeks prior to and after parturition (12-week range). We assessed the influence of tree canopy cover, impervious surface, normalized difference vegetation index (NDVI), distances to roads, buildings, and forest edges, and an urbanization index (i.e., position on the urbanization gradient) on birth-site selection. We developed 3 generalized linear mixed models (GLMMs) – a null model, a model with all covariates, and a model incorporating covariate-urbanization index interactions – and ranked them using Akaike’s Information Criterion for small sample sizes (AICc). The top model, which included only the covariates (i.e., no urbanization index interactions), indicated that landscape covariates affected selection similarly across the urban-rural gradient. Female deer, no matter their location on the gradient, selected birth sites with high NDVI that were closer to forest edges and roads, and farther from buildings. Percent impervious surface and tree canopy cover had no effect on selection. Our results indicate that female deer consistently select birth sites across the urban-rural gradient within or near areas that provide ample concealment cover to lower predation risk, and may also use areas in close proximity to roads as an anti-predation strategy.