Q: Why did it take so long for the USFWS to approve SonoBat for acoustic surveys?
A: Utterly simple: since initiating an acoustic survey protocol for Indiana bats in 2013 (and later for northern long-eared bats), the Service has only had legacy Anabat zero-cross files as testing material and could only evaluate software that uses zero-cross analyses. (Yes, that means previously approved software reduces full-spectrum data to zero-cross for processing.) SonoBat has followed the science to only use the higher information content of full-spectrum data and full-spectrum analyses. Only following the 2024 season did the USFWS have a sufficient library of full-spectrum recordings to begin developing the testing and evaluation of software that performs full-spectrum analyses.