Turbulence explains the accelerations of an eagle in natural flight

Soaring birds travel hundreds of miles without flapping their wings, and previous work has shown birds' ability to~utilize large-scale atmospheric flow structures such as thermal and orographic updrafts to enhance flight. However, it is~unclear what role turbulence plays in avian flight behavior. We analyzed acceleration and GPS data from a~golden eagle (\textit{Aquila chrysaetos}) and found that the bird's accelerations can be entirely explained by linear interactions with turbulence within an~interval of timescales between about 0.5 and 10 seconds. We isolated soaring flight from other behaviors by finding~patterns in the accelerations and by adapting known methods for behavior classification. From the position data, we approximated the wind speeds experienced by the golden eagle, which were between 2 and 13 m/s.~We found that the probability distribution function and the spectrum of the eagle's accelerations are non-Gaussian and~resemble those for lightly inertial particles in turbulence. Additionally, we find that higher wind speeds are associated~with larger accelerations, corresponding to a lifting of the spectra consistent with the increasing strength of turbulence~in higher winds.~