https://www.sciencedaily.com/releases/2018/09/180920101605.htm

The words "fly like an eagle" are famously part of a song, but
they may also be words that make some scientists scratch their heads. Especially
when it comes to soaring birds like eagles, falcons and hawks, who seem to
ascend to great heights over hills, canyons and mountain tops with ease.
Scientists realize that upward currents of warm air assist the birds in their
flight, but they don't know how the birds find and navigate these thermal
plumes.

To figure it out, researchers from the University of California San Diego used
reinforcement learning to train gliders to autonomously navigate atmospheric
thermals, soaring to heights of 700 meters--nearly 2,300 feet. The novel
research results, published in the Sept. 19 issue of Nature, highlight the role
of vertical wind accelerations and roll-wise torques as viable biological cues
for soaring birds. The findings also provide a navigational strategy that
directly applies to the development of autonomous soaring vehicles, or unmanned
aerial vehicles (UAVs).

"This paper is an important step toward artificial intelligence--how to
autonomously soar in constantly shifting thermals like a bird. I was surprised
that relatively little learning was needed to achieve expert performance," said
Terry Sejnowski, a member of the research team from the Salk Institute for
Biological Studies and UC San Diego's Division of Biological Sciences.

A navigational strategy was determined solely from the gliders' pooled
experiences collected over several days in the field using exploratory
behavioral strategies. The strategies relied on new on-board methods, developed
in the course of the research, to accurately estimate the gliders' local
vertical wind accelerations and the roll-wise torques, which served as
navigational cues.

Thanks to Jay Devorak, Miles Fragerlie and Dutcher Sterling.