Weather conditions affecting white-tailed deer harvest in Iowa

Abstract

Weather conditions, such as temperature and precipitation, likely influence white-tailed deer (Odocoileus virginianus) activity and hunter participation, both of which are major factors contributing to deer harvest. Because harvest is often used to manage white-tailed deer population trends and guide management decisions, understanding how certain abiotic factors may bias such data is important. We examined the effects of weather on deer harvest during the Iowa, USA, firearms seasons from 2006–2021 using a generalized mixed-effects linear model. Weather conditions during the hunting season were related to overall deer harvest. Specifically, deer harvest was positively correlated with snowfall on opening day and negatively correlated with average minimum temperature, average snow depth, rainfall on opening day, and number of rainfall and snowfall days. Abiotic factors have the ability to substantially influence deer harvest. Because many white-tailed deer population models use harvest data, incorporating the effects of weather variability into such models may substantially improve population estimates. Our study provides a compelling case for considering hunting season weather conditions when interpreting harvest data as a population index for white-tailed deer. The results of this study also demonstrate potential for retrospective modeling of past harvest rates and incorporating the effects of abiotic factors on harvest into future age-based population models.