An Evaluation of Western Chicken Turtle (Deirochelys reticularia miaria) Survey and Capture Protocols

Authors: Brandon C. Bowers, Danielle K. Walkup, Toby J. Hibbitts, Paul S. Crump, Wade A. Ryberg

The behaviors and activity season of Deirochelys reticularia miaria (Western Chicken Turtle) are poorly understood in Texas. Though distribution of D. r. miaria in the eastern portion of the state is widespread, turtle assemblage studies conducted within the range of the species in Texas have seldom documented its presence. There is a lack of formal protection for this subspecies and their habitat, and past research suggests that remaining habitat within the state is under threat from increasing urbanization. Therefore, the US Fish and Wildlife Service issued a 90-day finding that states listing the subspecies as threatened or endangered may be warranted. To provide survey recommendations for the western subspecies, we review species-wide capture techniques from the literature, recommend a survey season for D. r. miaria in Texas, and evaluate the efficacy and potential demographic biases of capture protocols implemented during field studies in the state in 2018 and 2019. We compared road surveys, dipnet surveys, seine surveys, night wading surveys, and two types of unbaited fyke net trap. Fyke nets were effective in every study that deployed them and captured D. r. miaria in this study at a rate of 0.25 captures per trap night. Dipnet surveys had the highest capture rate among active survey methods, but body size biases between methods were apparent. In Texas, road surveys yielded significantly lower capture rates than all other survey types. The best survey method selection will vary depending on research questions, budget, and time constraints. Utilizing proper survey protocols and understanding the activity season are crucial for performing effective studies on this species.

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