Abstract
This report presents the results of the bat survey for the proposed areas Kriegers Flak II OWF (North and South) from the first year between March 2023 and November 2023. The second-year survey program will be undertaken from April 2024 – November 2024. In spring 2023 (late March-early April) bat detectors were installed onshore on Stevns, Møn and at Gedser (Falster) in Denmark, at Falsterbo and near Skåre in southern Sweden and on the peninsula Darsser Ort on the Germany north coast. Bat detectors were also installed offshore on sixteen buoys in the pre-investigation areas for the Krieger Flak II (North and South). The bat detectors recorded the ultrasound from bats in the vicinity of the detector and saved the recording for later analysis. The range of the recording varies between the different bat species. Large bat, like common noctule and parti-colored bat can be recorded up to 100 meters from the detector, whereas smaller bat only can be recorded when they are within a distance below 50 meters.
Based on data from 1st year survey of the pre-investigation area for Kriegers Flak II it can be concluded that during spring and autumn migration several bat species occur. This indicates that migration take place in the area. Most likely this migration goes from Møn to Sweden in spring and from Sweden to Møn in autumn. In late summer and early autumn, in nights with high temperature and low wind speed, bats, most likely from Møn and Stevns use the pre-investigation areas for Kriegers Flak II for feeding. Most likely related to the presence of large insects over the open sea. In spring there are only very few recordings of bats, and all is nathusius pipistrel in late May, most likely on migration. Autumn migration of nathusius pipistrel is from late August until beginning of October. Migration of common noctule and parti-colored bat may occur in beginning of October. However, it is difficult to distinguish the migrating bat from feeding bat in this period. The recordings of bat are mainly from nights with low wind and high temperature. Recordings in nights with temperature lower than 17 C and wind speed over 7 m/s are very rare. The data collection will continue in 2024 and will strengthen the data set and provide better information on the pattern and the magnitude of the migration over the Kriegers Flak area and the feeding patterns of bats from the surrounding coastal areas.