Switching hierarchical leadership in coordinated movement of pigeon flocks

Coordinated animal behavior is abundant in nature, such as the uniform moving phenomenon among bird flocks, the collective evasion maneuvers of fish schools. To explore the appealing inter-individual interaction mechanism governing the abundant biological grouping behaviors, more and more efforts have been devoted to collective motion investigation in recent years. Previous research claims the existence of a well-defined hierarchical structure in pigeon flocks which implies that a leadership network leads to the occurrence of the highly coordinated pigeon flock movement. In this paper, by the assistance of the high-resolution GPS data of homing flight pigeon flocks, an explicit switching hierarchical mechanism is proposed. More precisely, a pigeon flock has a long-term positional leader for smooth moving trajectories, whereas the leadership passes to a tentative one upon sudden turns or zigzags. This mechanism is afterwards numerically verified to beneficial to improve the coordination efficiency. Therefore, the present observation helps explore more deeply into the underlying principle of a large volume of bird flocking motions. Meanwhile, it may shed some light on the decision making optimization of the social human group behaviors (like escaping panic evacuation), and industrial multi-agent systems' control.