Species-specific Trills by New World Big-eared Bats

Donald I. Solick^{1, 2, *}, Nicholas D. Solick^{1, 2}, and Rogelio M. Rodriguez³

¹Vesper Bat Echolocation Specialists, Fort Collins, CO 80524. ²Electric Power Research Institute, Palo Alto, CA 94304. ³Department of Fisheries, Wildlife & Conservation Sciences, Oregon State University, Corvallis, OR 97331. ^*Corresponding author.

Journal of North American Bat Research Notes, Volume 4 (2026):N1–N8

Abstract
Many bat species produce ultrasonic sounds for navigation and communication. Linking these sounds to specific species enhances acoustic monitoring and provides insights into the bats’ behavior and habitat use. In this study, we describe diagnostic trills produced by 3 North American species with large pinnae: Corynorhinus rafinesquii (Rafinesque’s Big-eared Bat), Idionycteris phyllotis (Allen’s Big-eared Bat), and Euderma maculatum (Spotted Bat). These species represent the only extant genera of the tribe Plecotini (Chiroptera: Vespertilionidae), suggesting that trilling may be a basal trait of this lineage. All 3 species produce long-duration oscillating tones (“continuous” trills) with a terminal pulse, differing in frequency and pulse-repetition rate. Euderma maculatum also emits a non-continuous “stutter” trill, composed of rapid, high-bandwidth pulses preceding a terminal pulse. We interpret these trills in the context of both echolocation and social vocalizations in bats, and we hypothesize that trilling is associated with singing behavior.

Download Full-text pdf (Open access)