New evidences confirm that during the breeding season Lesser Kestrel is not a strictly diurnal raptor

摘要

Although Lesser Kestrel Falco naumanni is considered a typically diurnal species, in a previous study we have provided the first report on its nocturnal activity in Italy even in rural areas with no artificial illumination. In this study, using new, more complete and balanced data we provide further evidences that during the breeding season Lesser Kestrel is not a strictly diurnal species. Using accurate GPS data-loggers on Lesser Kestrels belonging to the two colonies of Gravina in Puglia and Altamura (Apulia region; Southern Italy), we have registered widespread nocturnal flights with distances from nests up to 15 km. At night, all of the surveyed Lesser Kestrels were active even in areas with no artificial illumination, and they were found in flight for about 25% of the tracking time. By comparing night-time and daytime periods, we found significant differences for three flight attributes: 1-minute flight length, distance from nest and distance from nearest roost. Instead, we found no significant differences in flight attributes between males and females and between the two colonies at night. We propose and discuss several plausible explanations for detected Lesser Kestrels' nocturnal flight activities.