Changes in spectrotemporal features of echolocation signals in multiple bat assemblages

• Published in: The Journal of the Acoustical Society of America 2011-04, Vol.129 (4_Supplement), p.2470-2470
• Main Authors: Bates, Mary E., Knowles, Jeffrey M., Barchi, Jonathan R., Simmons, James A., Fujioka, Emyo, Watanabe, Yu, Furusawa, Yuto, Hiryu, Shizuko, Riquimaroux, Hiroshi
• Format: Article
• Language: English
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.3588123

Echolocating bats face potential acoustical interference when flying and foraging near echolocating conspecifics. Quantifying changes in the signal structure of echolocation emissions between bats flying alone and within a larger group has proven difficult. Here, we use two new methodologies, an onboard radio telemetry microphone and a multiple microphone array to record the sounds of big brown bats (Eptesicus fuscus) flying alone and in small groups both in the laboratory and in the field. In a laboratory flight room, bats changed the ending frequency of their first harmonic when the conspecific with which they were paired emitted calls at a similar frequency. In the field, ending frequency and sweep shape were more variable among groups of bats flying together than among single bats compared to one another. The presence of other nearby bats did not have any effect on the timing of emissions or the interpulse intervals [Work supported by NIH, NSF, ONR, and JSPS.]