Meeting Abstract
Bats use some of the fastest known vertebrate flight speeds and can forage thousands of meters above the ground, but it is unknown how they manage these high-energy behaviors. We tracked the three-dimensional movement of European free-tailed bats (Tadarida teniotis) in northeastern Portugal and developed high resolution wind models to test if bats use the underlying landscape and wind regime to generate high speeds and achieve high flight altitudes. Bats flew at speeds of 5.63 ± 3.66 m/s (maximum 41.24 m/s or 149 km/h) with airspeeds of 4.68 ± 3.79 m/s, (maximum of 37.52 m/s, 135 km/h). Bats largely follow the terrain at 182 ± 206 m above ground level (AGL), but appear to ride uplifting winds to travel hundreds of meters upwards in less than one minute to over 1600 m AGL. Predictive additive models using wind patterns alone are able to predict the location of these high-elevation ascents and explain 91.3% ± 11.1% of the deviance. This suggests that bats exploit the energy in vertical winds generated by the interaction between wind and topographic slope to minimize energetic expenditure, similar to diurnal birds, and likely follow a path of least resistance to high-elevation hunting grounds. Free-tailed bats generate some of the fastest powered flight speeds among vertebrates, forage at exceptional altitudes, and continue to challenge our understanding of flight in the wild.
