Landing together: how flocks arrive at a coherent action in time and space in the presence of perturbations

TL;DR

This paper presents a model of flock landing behavior showing how collective decision making occurs without a leader, highlighting that noise can paradoxically improve the coherence of the landing process.

Contribution

The authors introduce a simple phenomenological model based on self-propelled particles to explain how flocks coordinate landing times without a leader, applicable to broader decision-making scenarios.

Findings

Noise enhances the coherence of flock landing.

Heterogeneity in depletion times influences collective decision.

Model demonstrates egalitarian decision-making in animal groups.

Abstract

Collective motion is abundant in nature, producing a vast amount of phenomena which have been studied in recent years, including the landing of flocks of birds. We investigate the collective decision making scenario where a flock of birds decides the optimal time of landing in the absence of a global leader. We introduce a simple phenomenological model in the spirit of the statistical mechanics-based self-propelled particles (SPP-s) approach to interpret this process. We expect that our model is applicable to a larger class of spatiotemporal decision making situations than just the landing of flocks (which process is used as a paradigmatic case). In the model birds are only influenced by observable variables, like position and velocity. Heterogeneity is introduced in the flock in terms of a depletion time after which a bird feels increasing bias to move towards the ground. Our model demonstrates a possible mechanism by which animals in a large group can arrive at an egalitarian decision about the time of switching from one activity to another in the absence of a leader. In particular, we show the existence of a paradoxical effect where noise enhances the coherence of the landing process.