Semester of Graduation

Fall 2019

Degree

Master of Science (MS)

Department

Renewable Natural Resources

Document Type

Thesis

Abstract

Historically, Rio Grande wild turkeys in south central Texas have been at lower densities than other portions of the state. Within the Oak-Prairie Wildlife District of Texas, Rio Grande wild turkey regulatory restrictions are different for counties in the eastern and western portions of the ecoregion. Due to perceived increases in turkey density in the eastern portion of the ecoregion (hereafter 1-bird zone), Texas Parks and Wildlife Department (TPWD) considered increasing the bag limit to match counties in the western portion of the district (hereafter 4-bird zone) in order to increase hunting opportunities. However, if regulatory changes are to be considered in the absence of estimates of abundance and harvest rate, then estimates of demographic parameters will provide the basis for regulatory decision-making. Therefore, we evaluated reproductive metrics and breeding season survival for 138 radio-marked female Rio Grande wild turkeys in 4 counties in the 1-bird zone and 2 adjacent counties in the 4-bird zone. We also evaluated the influence of 6 nest- and female-specific covariates on survival of 131 nests. We found that reproductive timing varied little between zones and across years. Nesting and renesting rates were higher in the 1-bird zone (74% and 49%, respectively) than the 4-bird zone (63% and 25%, respectively). Conversely, nest and female success rates were higher in the 4-bird zone (18% and 15%, respectively) than in the 1-bird zone (2% and 3%, respectively). Nest survival analysis indicated higher daily nest survival in the 4-bird (0.94, SE = 0.01) than 1-bird zone (0.90, SE = 0.009). Female survival was similar between zones and was best explained by our model associated with daily distance moved. While causation is unclear, our results suggest that biologically significant differences potentially occur in basic reproductive parameters between regions within the Oak-Prairie Wildlife District of Texas, and that the proposed regulations change may not be appropriate given reproductive rates observed in the 1-bird zone.

Date

10-21-2019

Committee Chair

Collier, Bret

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