Behavioural plasticity and the transition to order in jackdaw flocks

Area of Science:

• Animal behaviour
• Collective dynamics
• Ecology

Background:

• Collective behaviour is often assumed to stem from fixed individual interaction rules.
• The adaptability of these interaction rules in different contexts remains under-explored.

Purpose of the Study:

• To investigate context-dependent variations in local interaction rules within wild jackdaw flocks.
• To understand how plasticity in interaction rules influences collective behaviour and group-level properties.

Main Methods:

• Observational study of wild jackdaw (Corvus monedula) flocks in different behavioural contexts (transit and anti-predator mobbing).
• Analysis of local interaction rules, distinguishing between topological (fixed neighbours) and metric (distance-based) interactions.
• Quantification of group density and collective order.

Main Results:

• Jackdaws employ topological interactions during transit and metric interactions during mobbing.
• Mobbing flocks show a density-dependent transition from disordered to ordered motion, unlike transit flocks.
• Observed density-order relationship in mobbing aligns with self-propelled particle models.

Conclusions:

• Local interaction rules in collective behaviour are not fixed and exhibit significant plasticity.
• Context-dependent interaction rules shape distinct group-level properties, influencing flock dynamics.
• Findings have implications for understanding collective systems in nature and artificial designs.