Murmuration

The lore states that the unusual flocking known as ‘murmuration’ is so named due to the immense murmur made by thousands of starlings flying together in tight formation. When birds are in a state of murmuration they fly as a single dynamic entity, the shape of the flock rapidly morphing like a weightless cohesive fluid. Even on an I-phone it is breathtaking to watch. Nick Dunlop is a master at capturing this phenomena in video form. Even after several viewings, I remain surprisingly touched when I watch this video. It is not that I have a special affection for individual starlings, but the way their murmuring shape moves reliably moves me.

The track of the murmuring flock is not like that found in the stately Vs of migrating water fowl. It’s true that the aerodynamically efficient V shape appears raggedy and rippling as the individual birds shift position, but the direction and speed of each bird’s flight is nearly identical, and changes in direction and speed occur relatively slowly. Murmuring starlings are flying in a variety of directions with different speeds, yet, we immediately recognize the organization, or coherence, in their flocking.

This dynamic coherence maintained by the flock gives the strong impression that it is a single being roiling and tumbling in the sky. The same sort of living coherence in the movement of bone and muscle tells me I am witnessing an animal moving. In fact, the electrochemical coherence of firing neurons seems essential to my witnessing anything at all. The murmuring of starlings induces a sympathetic swirling in me.

When a coyote lopes across the chaparral, her body is clearly the organizing entity that entrains the individual bones and muscles in an orchestrated movement. When starlings are in a state of murmuration there is no such organizing entity. Direct field observation, digitally captured, combined with the inevitable mathematical modeling, shows that no one bird, or group of birds, leads the flock. This analysis also demonstrates that individual starlings respond only to the handful of starlings nearest them, not to the flock as a whole. Individuals interact only with near neighbors, and yet the entire flock, consisting of mostly far-flung birds, maintains a coherent shape. It’s like an orchestral performance in which there is no score, no conductor, and the musicians play only in response to the notes played by a few other musicians near them. We might expect a cacophony, instead the performers play a beautiful symphony.

This type of ‘emergent’ behavior in a ‘many-body’ system is of keen interest to physicists, since it’s surprising and ubiquitous, describing many phenomena – from a metal’s phase transition as it enters the ferromagnetic state to a starling flock’s transition into the murmuration state.  (The scare quotes in the above sentence indicate real mathematical substance behind the terms). 

In the Nick Dunlop video the starlings enter into murmuration in response to being preyed upon by a raptor. The process of natural selection has very slowly crafted, over hundreds of thousands of generations at the least, this many-body starling response to the life-threatening presence of a falcon. This same process produced my capacity to delight in the murmuration’s beauty. Perhaps the starlings’ movement so easily reaches inside me because the poignancy of the mortal play with the falcon is expressed directly in the shape-shifting cloud.

Once I was driving along the north edge of San Pablo Bay, where the road stretches over marshy regions of still water. Traffic had slowed to a crawl, and in that leisure I looked to my left and saw hundreds of small shore birds flying in tightly choreographed swoops and whooshes. In the crepuscular light their turning bodies produced a staccato of black to white to silver and back, again and again, as they oozed and gathered over the insect rich still water. In the golden light, the water’s smooth surface reflected their dazzling flight.

As I watched, and nearly rolled into the car ahead of me, a goofball smile of delight spread across my face. The weave of my delight and gratitude was sufficiently fine that I had a hard time distinguishing them. My delight, the birds, the traffic, the universe, water and light – all part of a vast murmuration.