Dr. Kimberly Andrews

University of Georgia, Odum School of Ecology

• 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.
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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.

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.