Use of N-mixture models for estimating white-tailed deer populations and impacts of predator removal and interspecific competition

Abstract

Predation and competition can have significant effects on population dynamics. Range expansion of coyotes (Canis latrans) and the growing number of wild pigs (Sus scrofa) can negatively impact white-tailed deer (Odocoileus virginianus) populations. Traditional methods for estimating demographics, such as mark-recapture, can be labor intensive and difficult to implement on large scales. N-mixture models rely only on spatially and temporally replicated count data, and can be employed for large-scale monitoring. We evaluated the efficacy of N-mixture models for estimating deer populations, and estimated effects of predator removal and interspecific competition on deer population dynamics using N-mixture models. Time-lapse photography and N-mixture models provided accurate estimates of deer density and may be an effective method for surveying and monitoring deer. Our results indicate that short term coyote removal programs may negatively impact deer populations. Additionally, our data suggest that wild pigs are displacing or excluding deer from pulse food resources.