Data from: Common noctules exploit low levels of the aerosphere

• Main Authors: O'Mara, M. Teague, Wikelski, Martin, Kranstauber, Bart, Dechmann, Dina
• Format: Other/Unknown Material
• Language: unknown
• Published: Zenodo 2019
• Subjects: aeroecology; Bat; Nyctalus noctula; foraging
• Online Access: https://doi.org/10.5061/dryad.63q3283

Aerial habitats present a challenge to find food across a large potential search volume, particularly for insectivorous bats that rely on echolocation calls with limited detection range and may forage at heights over 1000 m. To understand how bats use vertical space, we tracked one to five foraging flights of eight common noctules (Nyctalus noctula). Bats were tracked for their full foraging session (87.27 ± 24 mins) using high-resolution atmospheric pressure radio transmitters that allowed us to calculate height and wingbeat frequency. Bats used diverse flight strategies, but generally flew lower than 40 m, with scouting flights to 100 m and a maximum of 300 m. We found no influence of weather on height and high-altitude ascents were not preceded by an increase in foraging effort. Wingbeat frequency was independent from climbing or descending flight, and bats skipped wingbeats or glided in 10% of all observations. Wingbeat frequency was positively related to capture mass, and wingbeat frequency was positively related to time of night, indicating an effect of load increase over a foraging bout. Overall, individuals used a wide range of airspace including altitudes that put them at increased risk from human-made structures. Further work is needed to test the context of these flight decisions, particularly as individuals migrate throughout Europe. Weather annotated foraging data Flight heights and wingbeat frequency are derived from atmospheric pressure radio transmitters. Weather data were collected from the German weather service, Deutscher Wetterdienst (DWD), and interpolated to the timestamps of the observed altitude data. Additional movement data are available at the Movebank Data Repository: doi:10.5441/001/1.7t4b97qf. Please see the README for data definitions. Noctule Altitude foraging pub data.csv Data README.txt