Meeting Abstract
Many birds soar cross country using thermal updrafts to gain or maintain altitude. Successful soaring requires the ability to detect and respond rapidly to subtle changes in the atmosphere, for example by sensing climb rate or vertical acceleration. Despite the extensive instrumentation available to human pilots to measure these quantities, birds are frequently able to outperform them whilst climbing in thermals. In this study we explore the soaring flight of a trained, captive Steppe Eagle Aquila nipalensis to determine the mechanisms and strategies that it uses when exploiting thermal lift. A customised instrumentation unit mounted on-board the bird was used to log GPS position, barometric altitude, linear acceleration, angular velocity, airspeed, and Earth magnetic field data over the course of 45 flights. Using an objective criterion combining yaw rate and climb rate thresholds, we identified over 175 sections of thermalling flight automatically from the data. Here we present data which characterise the thermal soaring behaviour of our bird such as circling radius, bank angle, lift coefficient, kinetic energy, potential energy, and wind drift. We also discuss our preliminary analysis comparing the soaring strategy of our bird with the various strategies employed by human glider pilots by analysing correlations between the bird’s banking behaviour and possible sensory stimuli.
