2017 Volume 37 Issue 144 Pages 14-19
Dynamical behavior of flying bird flocks is analyzed. From data of hooded gull flocks obtained by stereo camera system, three-dimensional positions of flock members are reconstructed. Their time series enable us to quantify the relative position, velocity and flapping motion of each individual. Their collective behavior is analyzed in terms of kinematics. The distribution of relative position clarifies that the shape of the flocks is thin, and the following birds avoid the position just behind the preceding bird. These features are consistent with the scenario of exploiting the aerodynamic effect of the wing edge vortices. The relation between the temporal delay of the moving direction and the spatial longitudinal relative position between the individuals are observed. Analysis of pigeon flocks obtained by GPS system is also introduced. By focusing on the free flight state, internal motion of the individuals in the turning flocks is characterized.
