Diffusion of individual birds in starling flocks

Area of Science:

• Collective Animal Behaviour
• Self-Organization Dynamics
• Avian Movement Ecology

Background:

• Collective animal behaviour, like flocking, demonstrates global order arising from local interactions.
• The dynamic nature of neighbour interactions in animal groups is crucial for information propagation and maintaining order.
• Understanding these dynamic networks is key to comprehending collective motion in species such as starlings.

Purpose of the Study:

• To investigate the relevance of dynamic neighbour interactions in large starling (Sturnus vulgaris) flocks.
• To quantify movement patterns and neighbour reshuffling in starlings.
• To explore the mechanisms underlying collective motion and information flow in avian flocks.

Main Methods:

• Analysis of movement data from large starling flocks.
• Comparison of individual bird speeds against Brownian motion models.
• Quantification of neighbour exchange rates and analysis of motion anisotropy.
• Investigation of flock border dynamics.

Main Results:

• Starling flocks exhibit speeds exceeding Brownian motion, both relative to the flock's center of mass and between individuals.
• Movement patterns are highly anisotropic relative to the flock's direction of travel.
• Neighbour reshuffling occurs primarily due to random motion, without evidence of active neighbour retention mechanisms.
• Complex dynamical processes were identified at the flock's periphery.

Conclusions:

• Dynamic neighbour interactions are essential for maintaining order and facilitating information transfer in starling flocks.
• The observed anisotropic and super-diffusive motion highlights the efficiency of collective movement in starlings.
• Flock border dynamics may play a significant role in group cohesion and response to external stimuli.