Field observations of ecoacoustic dynamics of a Japanese bush warbler using an open-source software for robot audition HARK

We report on a simple and practical application of HARK, an easily available and portable system for bird song localization using an open-source software for robot audition HARK, to a deeper understanding of ecoacoustic dynamics of bird songs, focusing on a fine-scaled temporal analysis of song movement — song type dynamics in playback experiments. We extended HARKBird and constructed a system that enables us to conduct automatic playback and interactive experiments with different conditions, with a real-time recording and localization of sound sources. We investigate how playback of conspecific songs and playback patterns can affect vocalization of two types of songs and spatial movement of an individual of Japanese bush-warbler, showing quantitatively that there exist strong relationships between song type and spatial movement. We also simulated the ecoa- coustic dynamics of the singing behavior of the focal individual using a software, termed Bird song explorer, which provides users a virtual experi- ence of acoustic dynamics of bird songs using a 3D game platform Unity. Based on experimental results, we discuss how our approach can contribute to ecoacoustics in terms of two different roles of sounds: sounds as tools and subjects.