A Perspective on Thermal Imagery for Bat Emergence Counts: Best Practices, Challenges, and Recommendations for the Future

Sonja E. Ahlberg^{1, 2}, Vona Kuczynska³, and Laura N. Kloepper^{1, 2, *}

¹Department of Biological Sciences, University of New Hampshire, 38 Academic Way, Durham, NH 03824.²Center for Acoustics Research and Education, University of New Hampshire, 24 Colovos Rd., Durham, NH 03824.³United States Fish and Wildlife Service, Missouri Ecological Services Field Office, 101 Park DeVille Dr., Suite A, Columbia, MO 65203.^*Corresponding author.

Journal of North American Bat Research, Special Issue 1 (2025):46–58

Abstract
Accurate information on population sizes is crucial for animal conservation and management. For bats, especially those that roost in large caves, this information can be challenging to obtain with visual or photographic methods, as bats often hide in cave crevices, emerge in low light conditions, and cease to emerge in artificial illumination. Recent advances in thermal imagery have made recording devices more affordable and easier to use, and thermal imagery has quickly become a viable option to record bat emergence for population counting. Researchers have developed automated bat counting software to process videos with favorable but variable results, and we believe camera quality and subjective user methodology are some of the biggest factors affecting automated counting software accuracy. Recognizing the importance of video quality, we compiled a perspective on using thermal imagery to record bats, including addressing its challenges and offering best practices for obtaining accurate census data.

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