Dr. Kimberly Andrews

University of Georgia, Odum School of Ecology

Background and Objectives


The gopher tortoise, a keystone species of the southeastern United States, is under review for Endangered Species Act protection. One major effort toward securing the species’ future involves relocating individuals from development sites (e.g., heavy mineral mining operations) to protected lands. This study aimed to determine if relocated females successfully integrate and reproduce within resident tortoise populations. A novel component of this research was investigating tortoise vocalizations—a largely unexplored aspect of their behavioral ecology. The objectives were to:

  • Deploy acoustic recorders (Wildlife Acoustics SM4 units) to monitor gopher tortoise vocalizations.
  • Characterize and classify vocalizations in both captive and wild settings.
  • Combine acoustic data with camera trap imagery and genetic analyses to link vocalizations to social and reproductive behaviors.
  • Assess integration success between translocated and resident tortoises through interactions and reproduction.

Methodology

Pilot and Field Deployments:
The study began with lab-based trials using juvenile tortoises (~1 year old) to calibrate equipment and software (Kaleidoscope Pro). Researchers then deployed five SM4 acoustic recorders across burrows at a Wildlife Management Area in Jesup, Georgia—focusing on burrows of relocated females.

Complementary Data Collection:

  • Wildlife camera traps captured visual confirmation of interactions.

  • Telemetry (GPS + VHF) tracked tortoise movement to adaptively reposition cameras and recorders.

  • Genetic sampling of hatchlings was conducted to determine parentage, providing reproductive confirmation.

Data Analysis Workflow:

  • Initial recordings averaged 220 hours/week.

  • Researchers cross-referenced confirmed interactions on camera with the corresponding acoustic data to identify vocalizations.

  • Kaleidoscope’s cluster analysis function was trained iteratively to detect tortoise-specific calls.

  • Manual verification was used to reduce false positives due to acoustic overlap with birds and amphibians.

Key Findings and Outcomes

Vocalization Discovery and Classification:

  • Over 6,300 gopher tortoise vocalizations were identified.

  • Eight distinct vocalization types were discovered, five of which were linked to specific behaviors (e.g., mating).

  • Most vocalizations occurred in the 0–6 kHz range, with some as low as 0–2 kHz—consistent with findings in other tortoise species.

  • Approximately 665 additional sound events were attributed to shell scraping or contact.

Individual Variation in Behavior:

  • A significant disparity in vocal activity was observed among individuals.

  • One resident female's burrow accounted for over 50% of total recorded vocalizations, exceeding 10 calls/hour—suggesting notable individual variability in social behavior or reproductive interest.

Conservation Implications:

  • Demonstrated potential integration of translocated females via observed interactions and confirmed reproduction.

  • Non-invasive acoustic monitoring paired with imagery and genetics provides a holistic tool for assessing population health and behavioral ecology.

  • These insights are critical for agencies managing tortoise populations, contributing to ESA status assessments.

Challenges and Adaptive Strategies

  • High rate of acoustic false positives required time-intensive manual validation.

  • Seasonal inactivity (winter burrow use) necessitated suspension of recording efforts and focus on data analysis.

  • Real-time repositioning of equipment required close coordination with telemetry data.

Download the poster

Outreach and Future Work

Presentations & Publications:

  • Poster presentation at the 40th Annual Gopher Tortoise Council Meeting (Archbold Biological Station, FL) received strong interest.

  • A peer-reviewed manuscript is in preparation outlining the methodology and early results.

Conclusion

This study marks one of the first comprehensive efforts to characterize and understand vocal behavior in gopher tortoises. By combining acoustics, camera data, telemetry, and genetics, the project provides a scalable model for non-invasive wildlife monitoring and species conservation—particularly for long-lived, cryptic reptiles whose social lives remain poorly understood. These findings not only offer tools for improving translocation success but also open the door to new questions in tortoise communication, reproduction, and conservation planning.