Factors influencing survival of female eastern wild turkeys in northeastern South Dakota

Abstract

AbstractPopulation growth can be sensitive to changes in survival rates for many avian species. Understanding sources of mortality, and how to mitigate negative effects on survival, can give managers insight into factors contributing to population change. Harvest trends of eastern wild turkeys (Meleagris gallopavo silvestris) in northeastern South Dakota suggest a decline in abundance. We investigated factors influencing survival of wild turkeys to identify potential factors contributing to the decline. We monitored 122 female wild turkeys using VHF radio transmitters from February 2017 to April 2019. Annual survival was 0.52 (95% CI = 0.33–0.64) for juvenile and 0.49 (95% CI = 0.23–0.63) for adult females, respectively. Daily survival probability was significantly lower during the spring (log‐odds ratio [LOR] = −0.9; 95% CI = −1.5–−0.2) and while a juvenile female was incubating (LOR = −0.67; 95% CI = −1.23–−0.09) but not while an adult female was incubating (LOR = −0.35; 95% CI = −0.92–0.24). Mammalian predation was the leading cause of mortality, and female wild turkeys were most vulnerable to predation during the spring while engaging in nesting and rearing of young broods. Wild turkeys were at risk for additional sources of mortality while incubating nests that were not contributors to mortality during other periods of the year, as deaths caused by haying equipment—the second greatest cause of mortality—only occurred while a female was incubating. Reducing female mortality due to haying, by delaying cutting, installing flushing bars on haying equipment, or increasing availability of suitable nesting cover types to reduce the probability of nesting in hayfields, could improve female survival. Annual survival during our study was about 16–29% lower than survival estimates from northeastern South Dakota during the 1990s, suggesting that reduced female survival could be contributing to the apparent decline in wild turkey abundance.