The nightingale citizen science project and its cooperation with the ‘Naturblick’ app

The nightingale citizen science project was launched in 2018 as a collaboration with the 'Naturblick' app at the Museum für Naturkunde (MfN) in Berlin, Germany. The app has been available since 2016 and has already been widely used in 2017 with almost 50,000 downloads (Sturm and Tscholl 2019). As a special feature, the app includes a pattern recognition algorithm (PRA) which automatically identifies bird species based on cross-correlation via template matching of spectrogram segments (Lasseck 2016; Stehle et al. 2020). During the last years, the PRA improved due to the use of neural networks as well as deep learning (Lasseck 2018).

Using diverse dissemination activities such as events both inside and outside the MfN, midnight excursions and press coverage, the public was invited to download the 'Naturblick' app on their smartphones and record nightingale songs (for details see Jäckel et al. 2021). Public events were free of charge, included two to 180 participants and by large took place in Berlin. Press coverage occurred mainly before and during the breeding season in the form of radio interviews, newspaper articles and social media posts. The app featured a bespoke button showing a nightingale, to highlight the citizen science project. By clicking on this button, participants could transmit their recordings directly or make use of the PRA to aid in species identification (Fig. 1). As part of this process, the three bird species whose vocalisations most closely match the recording were presented (Stehle et al. 2020). Participants were also allowed to choose whether they wanted to submit the recordings anonymously or non-anonymously with an individual username. Because of technical limitations, it was not possible to submit recordings more than once or with a duration of more than two minutes per recording. Temporal (day, time) and spatial (GPS coordinates) information were automatically captured in the metadata, if permitted by the participant.

Left: Process of song recording transmission. Middle: Display of the ‘Naturblick’ app. Right: For data transmission, users could participate anonymously or non-anonymously and either make use of the pattern recognition algorithm or directly submit the recording