Bio-acoustic tracking and localization using heterogeneous, scalable microphone arrays

Verreycken and colleagues present a methods paper detailing construction of large, scalable microphone arrays for bio-acoustic monitoring of animal species. They demonstrate the efficacy of their method in detailing bat hunting echolocation beams with a 64-microphone array, and localizing songbirds across a larger habitat. Microphone arrays are an essential tool in the field of bioacoustics as they provide a non-intrusive way to study animal vocalizations and monitor their movement and behavior. Microphone arrays can be used for passive localization and tracking of sound sources while analyzing beamforming or spatial filtering of the emitted sound. Studying free roaming animals usually requires setting up equipment over large areas and attaching a tracking device to the animal which may alter their behavior. However, monitoring vocalizing animals through arrays of microphones, spatially distributed over their habitat has the advantage that unrestricted/unmanipulated animals can be observed. Important insights have been achieved through the use of microphone arrays, such as the convergent acoustic field of view in echolocating bats or context-dependent functions of avian duets. Here we show the development and application of large flexible microphone arrays that can be used to localize and track any vocalizing animal and study their bio-acoustic behavior. In a first experiment with hunting pallid bats the acoustic data acquired from a dense array with 64 microphones revealed details of the bats' echolocation beam in previously unseen resolution. We also demonstrate the flexibility of the proposed microphone array system in a second experiment, where we used a different array architecture allowing to simultaneously localize several species of vocalizing songbirds in a radius of 75 m. Our technology makes it possible to do longer measurement campaigns over larger areas studying changing habitats and providing new insights for habitat conservation. The flexible nature of the technology also makes it possible to create dense microphone arrays that can enhance our understanding in various fields of bioacoustics and can help to tackle the analytics of complex behaviors of vocalizing animals.

Automated summary

Verreycken and colleagues have developed a large, flexible microphone array system for bio-acoustic monitoring of animal species, which allows for detailed study of animal vocalizations and behavior without intrusive methods. The technology has been successfully used in experiments monitoring bat echolocation beams and localizing songbirds within their habitat. The flexibility of the microphone array system allows for simultaneous tracking of multiple species, making it a valuable tool for studying complex behaviors of vocalizing animals.