Reproductive parameters of Rio Grande wild turkeys on the Edwards Plateau, Texas

Authors: K. B. Melton, J. Z. Dreibelbis, R. Aguirre, J. B. Hardin, N. J. Silvy, M. J. Peterson, B. A. Collier

Rio Grande wild turkey (Meleagris gallopavo intermedia) abundance has declined in portions of the Edwards Plateau of Texas since the late 1970s. Because reproductive performance influences population dynamics, our objectives were to evaluate how hen reproductive activities varied between areas of stable and declining populations. We evaluated productivity metrics of 304 radiotagged Rio Grande wild turkey hens over 7 reproductive seasons (2001–2007) from areas with stable and declining populations on the Edwards Plateau. First, we evaluated the influence of temporal variation on nest survival using data collected during the entire study. Second, based on intensive reproductive ecology work during 2005–2007, we evaluated impacts of nest- and hen-specific information (n = 162) on nest survival. Nest survival during 2001–2007 varied temporally within years following a consistent trend associated with nest initiation dates. We found a 2-period trend best fit the data where daily nest survival varied between the first 20 days of the breeding season (0.92, SE = 0.02, 95% CL =0.88–0.94) and the last 97 days of the breeding season (0.94, SE = 0.005, 95% CL = 0.93–0.95). Hen nesting rates were variable among years in stable versus declining sites with 78%, 85%, and 94% attempting to nest in the stable region and 67%, 46%, and 87% attempting to nest in the declining region during 2005–2007, respectively. Using data on nest- and henspecific covariates, daily nest survival increased as hen age increased and the percentage of hens attempting to nest increased. We suggest that nest survival was not related to declines in wild turkey abundance and that any perceived declines were likely a function of variation in production potential (percentage of hens nesting), nesting rates, and nesting hen survival.

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