Sakamoto Y., Oizumi S., Bundo H., Mikami K. & Mikami O.K. (2025) Quantifying Eurasian Skylark song flight altitudes using a laser rangefinder. ARDEA 113 (2): 195-203

The Eurasian Skylark Alauda arvensis performs an aerial display flight to altitudes of over 100 metres while singing continuously for extended periods; a striking behaviour among avian aerial displays. Despite this conspicuous display, previous studies recorded only maximum altitudes and did not measure continuous flight trajectories. In this study, we used handheld laser rangefinders to obtain fine-scale and continuous altitude profiles of Eurasian Skylark song flights in Hokkaido, Japan. In total, we recorded 203 flights, of which 147 were complete from take-off to landing. Maximum altitude ranged from 10 to 179 m (mean = 73.6 m, median = 69.4 m), whereas flight duration ranged from 27 to 487 s (mean = 129.5 s, median = 98.0 s). Maximum altitude increased with flight duration but tended to plateau at approximately 150 m. Environmental variables (wind speed, temperature, time of day) showed no clear association with maximum altitude. Continuous recordings revealed three altitude-trajectory patterns: table-shaped (28 flights), mountain-shaped (46 flights) and waveshaped (11 flights). Mountain-shaped flights were more frequent earlier in the morning, whereas wave-shaped flights occurred more often during longer-duration song flights. Taken together, our results demonstrate that skylark song flights are not confined to the conventional climb-level-descent pattern. By quantifying trajectories across entire display flights, this study provides a baseline for future research into the ecological and social significance of this behaviour.