American Scientist

July-August 2025

Volume: 113 Number: 4

Unseen animals can often still be heard. That’s part of the impetus behind the growing field of ecoacoustics, which aims to measure entire soundscapes in different habitats as a way of gauging an ecosystem’s health over time. Becky E. Heath and her colleagues have been particularly interested in studying the tropical rainforests of Malaysian Borneo, as shown on the cover. But first, as Heath details in “The Ecoacoustics of Forests” they have to be able to make reliable, high-quality, directional recordings. Heath and her colleagues have been working on a spatial recording device, shown at center, which incorporates multiple microphones that each can pinpoint the direction from which a sound originates. The microphones also operate without any recording delays that would cause error in calculations of sound distance or direction. Working with animal sound databases and machine learning technologies, Heath and her team have shown that their recordings can be used to estimate species abundance in different areas. (Cover art by Beatriz Ortiz.)