Analyzing the acoustic parameters of bird vocalizations and their perceived pleasantness by humans

Some bird sounds are perceived as more pleasant and restorative than others. Determining the specific acoustic parameters that are associated with pleasant sound experiences for humans and how this might be related to birding specialization and how much listeners value birds has not been studied yet. Here, we asked German adult listeners in a lab study to rate the sound pleasantness of bird vocalizations of 123 European bird species. We further measured frequency, amplitude and bandwidth and related them to perceived sound pleasantness. Moreover, we investigated if sound pleasantness is related to the total number of elements and sound complexity of a sound. Bird sounds with higher low and peak frequencies, but lower amplitude and high frequency and a narrower bandwidth were perceived as more pleasant. Additionally, sounds with higher complexity were associated with higher pleasantness ratings. Lastly, participants who value birds more, rated sounds more pleasant. Birding specialization, however, was unrelated to perceived pleasantness, indicating that this measure is not dependent on knowledge or bird-related activities. Our findings highlight which species are associated with acoustic pleasantness in human perception which might be beneficial in evaluating, maintaining and improving the recreational value of natural spaces.