Movie 1

Frontal view video of Goshawk and Tawny Owl passing through illuminated bubble volume. Clips begin at the first frame the volume is illuminated. These views are for context only and were not used in the particle tracking. Recorded at 120 frames per second, shown at 24 fps. Exposure duration 1/140s, or 5/700s, resulting in exactly five 1/7000s strobe flashes each frame. Wingtip trailing vortices persist in the wake, and regions of faster downwash and associated tail tip vortices convect downward following the tail indicating a step increase in lift over the body/tail section.

High aerodynamic lift from the tail reduces drag in gliding raptors

James R. Usherwood, Jorn A. Cheney, Jialei Song, Shane P. Windsor, Jonathan P. J. Stevenson, Uwe Dierksheide, Alex Nila, and Richard J. Bomphrey

Journal of Experimental Biology 2020. 223:None-None; doi: 10.1242/jeb.214809