The soundscape methodology for long-term bird monitoring: A Mediterranean Europe case-study

The soundscape represents the acoustic footprint of a landscape, and may well be a source of a vast amount of information that could be used efficiently in, for example, long-term bird aggregation monitoring schemes. To depict such soundscape footprint, specific indexes are requested. In particular, the aim of this paper was to extensively describe the Acoustic Complexity Index (ACI) and to successively apply it to process the sound files recorded in an ecologically fragile area in a Mediterranean maqui (Eastern Liguria, Italy). Daily acoustic animal activity was sampled in 90 one-minute files between the end of May and the end of July, 2010, using a pre-programmed recording procedure (Songmeter, Wildlife Acoustic). The WaveSurfer software, powered by the Soundscape Metric plug-in, was then utilized to quickly process these data.This approach allows the identification of the compositional changes and acoustic fluctuations activity of a local community (in the proposed case prevalently composed by birds and cicadas). In particular, two distinct patterns emerged during the investigation. From 20 May to 4 July, the soundscape was dominated by birds but, after that period, the onset of the cicadas' songs completely changed the sound dynamics. The proposed methodology has been demonstrated to be a powerful tool to identify the complex patterns of the soundscape across different temporal scales (hours, days and intraseason). This approach could also be adopted in long-term studies to monitor animal dynamics under different environmental scenarios.

► Daily and seasonal patterns of the bird soundscape in a Mediterranean maqui is investigated from May to July 2010. ► The Acoustic Complexity Index (ACI) is applied on a WaveSurfer platform, using an appositively developed plug-in. ► The onset of cicada songs in July extensively masks bird acoustic behavior. ► This methodology allows to quickly track soundscape fluctuations both in frequency and time. ► ACI is an efficient tool for animal long-term monitoring.