Detector-based surveys were carried out during the excursion in May 2023 to determine bat activity on Giglio. The recordings were made using ultrasonic detectors, which enable real-time recording and thus differentiated species diagnostics.

The survey was carried out on foot. A bat detector with ultrasonic diaphragm microphones (Wildlife Acoustics Echometer Touch 2 for iOS smartphones) was used. The ultrasonic detector records sounds in the range from 10 to 138 (or 150) kHz. In addition to the frequency, the echometer offers identification suggestions via the associated app. The recordings were subsequently analysed using the BatExplorer programme from Elekon. The study area in the various habitats on the island was covered with the ultrasonic detector from sunset to midnight. Stops were made for 5 to 10 minutes at suitable locations.

In addition, stationary loggers (Elekon Batlogger S2) were set up at selected locations in various habitats for one to two nights, which independently recorded bat calls until the next morning. The locations of the study sites were chosen so that all habitat types and structures relevant to the bats were taken into account. No surveys were carried out or stationary loggers deployed on rainy days.

The study area covers various habitats, including maquis/garigue, cliffs (allume), holm oak forest and urban areas around the town of Campese. The selection of the sites was based on their accessibility on foot.

A stationary logger on the Allumne.