Nocturnal flights lead to collision risk with power lines and wind farms in Lesser Kestrels: a preliminary assessment through GPS tracking

Abstract

We present here the first report about Lesser Kestrels' flight height behaviour and potential collision risk with wind farms and power lines in two colonies (Gravina in Puglia and Altamura; Apulia, Italy) that present the highest density of Lesser Kestrels worldwide in urban areas. Using accurate GPS data-loggers on nine Lesser Kestrels, we collected data on flight activities during the nestling period. The tracked Lesser Kestrels spent 50% of the monitoring time at heights above ground level (AGL) lower than 41 m, and 75% of time below 98 m AGL. Flight heights resulted not significantly different between the two colonies. Instead, at night Lesser Kestrels resulted to fly at significantly lower altitudes than in the daytime. Our findings, although preliminary, underline the potential collision risk with power lines and wind farms at night in the Lesser Kestrels' colony of Gravina in Puglia. Instead, collision risk resulted negligible during the daytime for both colonies. We conclude that the disappearing of pseudo-steppes in the study area is forcing Lesser Kestrels to flight also at night for foraging purposes during the breading season, which in turn leads to an increased risk of collision with power lines and wind farms