Cooperative Fish and Wildlife Research Units Program: Georgia
Education, Research and Technical Assistance for Managing Our Natural Resources

Georgia Project


Head-Starting as a Recovery Strategy for the Desert Tortoise

August 2014 - December 2021


Personnel

Participating Agencies

  • University of Georgia, Savannah River Ecology Laboratory

The Mojave Desert tortoise (Gopherus agassizii) population, classified as Threatened under the U.S. Endangered Species Act, is in decline and in need of active management for population recovery. The rearing of neonate tortoises until they are more likely to survive (head-starting) is one strategy for population augmentation. Although head-starting has intuitive appeal as a conservation strategy, the strategy is expensive, and its success depends on how soon and how successfully head-started animals reproduce in the wild compared to wild-reared animals. While the husbandry phase of captive tortoises is well understood, the function and performance of head-started tortoises once released in the wild have not been evaluated. This research is conducted in collaboration with the University of Georgia’s Savannah River Ecology Laboratory, University of California-Davis, and National Park Service. This research will be used by conservation agencies and their partners to weigh trade-offs between the costs of head-starting against the expected benefit of head-starting to enhance tortoise population growth and persistence.

Research Publications Publication Date
Daly, J. A., K. A. Buhlmann, B. D. Todd, C. T. Moore, J. M. Peaden, and T. D. Tuberville. 2018. Comparing growth and body condition of indoor-reared, outdoor-reared, and free-ranging juvenile Mojave Desert Tortoises. Herpetological Conservation and Biology 13:622-633. http://www.herpconbio.org/Volume_13/Issue_3/Daly_etal_2018.pdf | Download December 2018
Daly, J. A., K. A. Buhlmann, B. D. Todd, C. T. Moore, J. M. Peaden, and T. D. Tuberville. 2019. Survival and movements of head-started Mojave desert tortoises. Journal of Wildlife Management 83:1700-1710. DOI: 10.1002/jwmg.21758 | Download September 2019
McGovern, P. A., K. A. Buhlmann, B. D. Todd, C. T. Moore, J. M. Peaden, J. Hepinstall-Cymerman, J. A. Daly, and T. D. Tuberville. Comparing husbandry techniques for optimal head-starting of the Mojave Desert Tortoise (Gopherus agassizii). Herpetological Conservation and Biology 15:626-641. http://www.herpconbio.org/Volume_15/Issue_3/McGovern_etal_2020.pdf | Download December 2020
McGovern, P. A., K. A. Buhlmann, B. D. Todd, C. T. Moore, J. M. Peaden, J. Hepinstall-Cymerman, J. A. Daly, and T. D. Tuberville. 2020. The effect of size on post-release survival of head-started Mojave desert tortoises. Journal of Fish and Wildlife Management 11:494-506. https://doi.org/10.3996/JFWM-20-014 | Download December 2020
Presentations Presentation Date
Daly, J. A., K. A. Buhlmann, B. D. Todd, C. T. Moore, J. M. Peaden, and T. D. Tuberville. 2017. Survival estimates and mortality risk factors for indoor head-started, outdoor head-started, and directly released juvenile desert tortoises (Gopherus agassizii) in the eastern Mojave Desert. Desert Tortoise Council Symposium, 24-26 February 2017, Las Vegas, NV. February 2017
Daly, J. A., K. A. Buhlmann, B. D. Todd, C. T. Moore, J. M. Peaden, M. M. Kern, and T. D. Tuberville. 2016. Comparing neonate survivorship and growth of Mojave desert tortoises (Gopherus agassizii) under 3 head-start treatments. The Wildlife Society 23rd Annual Conference, 15-19 October 2016, Raleigh, NC. October 2016
Daly, J. A., K. A. Buhlmann, B. D. Todd, C. T. Moore, J. M. Peaden, M. M. Kerr, and T. D. Tuberville. 2016. Evaluating indoor-rearing as a component of head-starting the Mojave Desert tortoise: methods and preliminary results. 41st Annual Meeting and Symposium of the Desert Tortoise Council, 19-21 Feb 2016, Las Vegas, NV. February 2016
McGovern, P., J. Hepinstall-Cymerman, C. Moore, B. Todd, T. Tuberville, and K. Buhlmann. 2018. [Poster] Changing the survival formula through head-starting the Mojave Desert Tortoise (Gopherus agassizii). Presentation at 2018 Annual Southeast Partners in Amphibian and Reptile Conservation, 22-25 February 2018, Helen, GA. February 2018
McGovern, P., K. Buhlmann, B. Todd, C. T. Moore, J. M. Peaden, J. Hepinstall-Cymerman, and T. Tuberville. 2019. Post-release movement and survival until dormancy of hybrid head-started Mojave desert tortoises (Gopherus agassizii). Annual Desert Tortoise Council Symposium, 21-23 February 2019, Tucson, AZ. February 2019
McGovern, P., K. Buhlmann, B. Todd, C. Moore, J. M. Peaden, and T. Tuberville. 2019. Post-release movement and survival of differentially head-started Mojave desert tortoises (Gopherus agassizii): Preliminary results. Oral presentation at Annual Meeting of the Southwest Partners in Amphibian and Reptile Conservation, 27-29 July 2019, Rodeo, NM. July 2019
McGovern, P., K. Buhlmann, B. Todd, C. Moore, J. M. Peaden, and T. Tuberville. 2019. Post-release movement and survival of differentially head-started Mojave desert tortoises (Gopherus agassizii): Preliminary results. Oral presentation at Annual Symposium on the Conservation and Biology of Tortoises and Freshwater Turtles, 4-8 August 2019, Tucson, AZ. August 2019
Theses and Dissertations Publication Date
Daly, J. A. 2017. Indoor-rearing as a component of head-starting the Mojave Desert Tortoise (Gopherus agassizii). M.S. thesis, University of Georgia, Athens. May 2017
McGovern, P. A. 2019. Changing the survival formula for the Mojave desert tortoise (Gopherus agassizii) through head-starting. M.S. Thesis, University of Georgia, Athens December 2019