  Gliding saves much energy, and to make large distances using only this form
of flight represents a great challenge for both birds and people. The solution
is to make use of the so-called thermals, which are localized, warmer regions
in the atmosphere moving upwards with a speed exceeding the descent rate of
bird and plane. Whereas birds use this technique mainly for foraging, humans do
it as a sporting activity. Thermalling involves efficient optimization
including the skilful localization of thermals, trying to guess the most
favorable route, estimating the best descending rate, etc. In this study, we
address the question whether there are any analogies between the solutions
birds and humans find to handle the above task. High-resolution track logs were
taken from thermalling falcons and paraglider pilots to determine the essential
parameters of the flight patterns. We find that there are relevant common
features in the ways birds and humans use thermals. In particular, falcons seem
to reproduce the MacCready formula widely used by gliders to calculate the best
slope to take before an upcoming thermal.
