The data collection system consists of the stereo camera rig and a laptop powered by an uninterrupted power supply (UPS). The data collection system consists of the stereo camera rig and a laptop powered by an uninterrupted power supply (UPS). A capture signal is sent from the frame grabber to record frames in sync. A Kestrel weather station records environmental factors such as temperature and wind velocity at 0.1 Hz. (Online version in colour.) Sachit Butail et al. J. R. Soc. Interface 2012;9:2624-2638 This journal is © 2012 The Royal Society