Murmuration Imagination: If our Children were Starlings!

Self regulation seems to come so easy to starlings...

What is going on here? How do these birds in this homogenous flock manage to maintain their equilibrium? Researchers think that starlings fly in these coordinated patterns for many reasons. The most obvious appears to be self-preservation. It's good to be in the herd -- not limping alone in tall grass out in the savanna. Grouping together offers safety in numbers – predators find it hard to target one bird in the middle of a hypnotizing flock of thousands.

How does each starling know when to turn?

In 2008, researchers in Rome published a paper in the journal Animal Behavior in which they analyzed high-quality video footage of 2,700 starlings in flight.(1) They noted that individual birds keep a minimum distance from their neighbors, proportional to their wingspans. Other research that year using similar analysis revealed that individual birds in flight coordinate their movements based on observations of six to seven birds around them.

Critical Transitions

When high-powered video analysis and computational modeling are applied to starling flocks they reveal patterns known less from biology than cutting-edge physics.(2) Starling flocks, it turns out, are best described with equations of “critical transitions” — systems that are poised to tip, to be almost instantly and completely transformed, like metals becoming magnetized or liquid turning to gas. Each starling in a flock is connected to every other. When a flock turns in unison, it’s a phase transition.

The molecular behavior of a body — whether it's ice in a hot room or a murmuration in flight — changes until it reaches a point where it can no longer exist in its current form. It becomes something else. It melts if its ice; it turns left if its in a flock of starlings.

Rules

At the individual level, the rules guiding phase transition are relatively simple. When a neighbor moves, so do you. Depending on the flock’s size and speed and its members’ flight physiologies, the large-scale pattern changes. What’s complicated, or at least unknown, is how criticality is created and maintained. 

It’s easy for a starling to turn when its neighbor turns — but what physiological mechanisms allow it to happen almost simultaneously in two birds separated by hundreds of feet and hundreds of other birds? That remains to be discovered, and the implications extend beyond birds. Starlings may simply be the most visible and beautiful example of a biological criticality that also seems to operate in proteins and neurons, hinting at universal principles yet to be understood. 

References

Ballerini, M., Cabibbo, N., Candelier, R., Cavagna, A., Cisbani, E., Giardina, I., . . . Zdravkovic, V. (2008). Empirical investigation of starling flocks: a benchmark study in collective animal behaviour. Animal Behaviour, 76(1), 201-215.

Keim, B. (2011). The Startling Science of a Starling Murmuration. Wired. Retrieved from https://www.wired.com/2011/11/starling-flock/