WarbleR: an r package to streamline analysis of animal acoustic signals

Abstract

Summary Animal acoustic communication is one of the most fruitful research areas in behavioural and evolutionary biology. Work in this area depends largely on quantifying the structure of acoustic signals, which has often depended upon closed‐source or graphical user interface (GUI)‐based software. Here, we describe the r package warbleR, a new package for the analysis of animal acoustic signal structure. The package offers functions for downloading avian vocalizations from the open‐access online repository Xeno‐Canto, displaying the geographic extent of the recordings, manipulating sound files, detecting acoustic signals or importing detected signals from other software, assessing performance of methods that measure acoustic similarity, conducting cross‐correlations, measuring acoustic parameters and analysing interactive vocal signals, among others. Functions working iteratively allow parallelization to improve computational efficiency. We present a case study showing how warbleR functions can be used in a workflow to evaluate the structure of acoustic signals. We analyse geographic variation in long‐billed hermit hummingbirds (Phaethornis longirostris) songs obtained from Xeno‐Canto. The code in warbleR can be executed by less experienced r users, but has also been thoroughly commented, which will facilitate further customization by advanced users. The combination of the tools described here with other acoustic analysis packages in r should significantly expand the range of analytical approaches available.