Broadcast supplemental feeding and northern bobwhite demographics in Texas

Abstract

Northern bobwhite (Colinus virginianus) abundance is declining. Food limitations have been hypothesized to exacerbate the boom and bust cycle exhibited by bobwhites, with supplemental feeding advocated as a way to mitigate this annual variability in demographics. A new technique (i.e., broadcast feeding) has exhibited positive effects on the seasonal survival of bobwhites. To ensure the safe adoption of any management practice, replication is necessary. We employed a randomized, crossover experimental design to evaluate the effect of 3 different supplemental feed rates (full [69.1 kg/km], half [34.6 kg/km], control [no feed]) on bobwhite survival and used the known-fate data type to assess the fate of radio-marked individuals within the Rolling Plains of Texas, USA. We assessed temporal (biological vs. calendar season) and treatment-level (feed vs. control) effects on survival. Our top temporal model included an interaction between year and calendar season as the most parsimonious model. Survival was lowest during winter. The most parsimonious treatment-level model included an interaction between feed and winter, plus the additive effect of snow depth. The application of the full and half feed treatments had positive effects on survival during winter compared to control units in both years, across all pastures. Our data indicated there was no difference between the full and half feed rates. Snow accumulation had a negative effect on survival in both years. Broadcast feeding improved winter survival rates and subsequently, the number of females available entering the breeding season. Broadcast feeding serves as an additional management tool for wildlife managers within a strategic management program to benefit bobwhite survival during periods of physiological stress. We recommend the continued use of this management technique in regions where similar range and weather conditions exist to further evaluate its effectiveness. © 2018 The Wildlife Society.