Effects of predator reduction on Northern bobwhite nest success and chick survival in the Rolling Plains of Texas

Predation as the leading cause of nest failure of Northern bobwhites (Colinus virginianus) has a long line of documentation. However as of late, it has evolved into a greater concern due to declines in bobwhite populations. My research aims to test the hypothesis that predator management can increase bobwhite populations in the Rolling Plains of Texas. To examine the effects of mammalian predator reduction on Northern bobwhites, my study aims to estimate nest success and chick survival. I collected data at the 6666 Ranch in Guthrie, Texas from January to August 2018 and 2019.Research plots consisted of four units totaling 2,428 ha. I defined nest success as at least one chick hatched, whereas chick survival was estimated by marking chicks with patagial tags 2 days post hatch and suturing radio-transmitters to chicks 9 days post hatch. Chicks were detected once per day post suture. Across both years I removed 30 predators and monitored 67 nests and 250 chicks. I used logistic-exposure and Akaike information criterion model selection. All models for nest survival had lower AIC values than the null model whereas a separate analysis indicated an additive model for average maximum wind and total rainfall was the best predicator of chick survival during the first seven days post hatch. When comparing chick survival based solely on predator removal throughout the duration of my study, modeling daily survival rate separately between treatment and control was competitive while the null was below the significance threshold. The daily survival rate of chicks in control was 0.916 (95% CI: 0.886 – 0.938) whereas the daily survival rate for chicks in treatment was 0.948 (95% CI: 0.931 – 0.961). With these rates, chick survival to 21 days was 15.7% for control and 32.8% for treatment. My results are promising for the efficacy of predator removal to benefit bobwhite reproduction; however, more data is needed in areas of the Rolling Plains of Texas especially where predator abundance indices ≥ 0.15.