Communication calls of little brown bats display individual-specific characteristics.

Bats' echolocation signals have been shown to be situation-, colony-, and individual-specific, but whether or not these findings apply to bats' communication signals is not fully understood. The primary goal of this study was to test the hypothesis that the communication calls of adult little brown bats (Myotis lucifugus) are individual specific. Bats were paired to form focal pairs from June 2007 to August 2008. Each bat's vocalizations were recorded on a PC-based digital recorder with a custom made ultrasonic microphone. The vocal signals were first classified using a previously established classification scheme. Three acoustic parameters (the minimum and maximum frequencies, and the call duration) of two of the dominant call-types, the steep-FM and broadband noise bursts, of individual bats were further analyzed. Discriminant function analysis, and multi- and univariate analyses of variance of these parameters revealed that these vocal signals were individually distinct and likely contain individual signatures to allow bats to identify individuals acoustically.