Investigating the individual difference in distance calls of Bengalese finches using acoustic analysis

Abstract

Most songbirds are monogamous and exhibit biparental care. They socially interact with other individuals, including those outside the family, through auditory modality. The capacity to explicitly identify conspecific individuals via acoustic cues enables fast turn-taking communication in a crowd, especially when visual signals are not available. Bengalese finches (Lonchura striata var. domestica) are domesticated strains of the white-rumped munia imported from China to Japan about 260 years ago. Previous studies have reported distance calls, which are emitted when a bird is visually separated from its conspecifics, are sexually dimorphic (both acoustically and perceptually) in Bengalese finches. However, the individuality in distance calls has not been thoroughly discussed yet. In this research, we recorded vocalizations from four pairs of Bengalese finches in kinship. To extract distance calls from those recordings, we use the Harmonics-to-Noise Ratio (HNR) to detect and remove noise, which mainly consists of aperiodic components. By analyzing acoustic features such as length, bandwidth, and peak frequency, we found that calls from the same individuals form clear clusters, and the difference between other individuals was more pronounced in contrast to kins. [Work supported by MEXT/JSPS grant #4903, 17H06380.]