Illustration “Murmuration” by artist Glenn Wolff
If you’ve ever watched flocks of starlings (or have seen them on YouTube), you’ve probably been enchanted by those swirling, switching clouds of birds. Have you ever wondered what causes them? Or why they’re called “murmurations”?
Starlings are a scourge. They crowd out native birds, spread disease, and steal mountains of grain. It was a thick-headed decision for a chemical-company executive named Eugene Schieffelin to carry them across the Atlantic in the 1890s and release them into Central Park because he thought it’d be cool if all the birds mentioned by Shakespeare were in America.
We know now what a bad idea that was. But starlings are here to stay, so we might as well accept them. And the fact is, they’re interesting — and beautiful. Examine one up close and you’ll see plumage stippled with stars strewn across a background of black and iridescent purple.
A few years ago, I was driving on a highway in the agricultural flatlands of Michigan. Across a field, at a distance of perhaps a mile, I saw what I thought was a plume of smoke hanging low in the sky. Then I realized it was a flock of thousands or tens of thousands of birds. In North America, such flocks often include red-winged blackbirds, cowbirds, grackles, sparrows, and others, but almost certainly they are comprised mostly of starlings.
This flock was extraordinary. First, it was vast: a stadium’s worth of birds. It was too far away to pick out individuals, which made the aggregate smokelike, a thick cloud of bird-smoke. It drifted in whorls above the field, curving and swirling as if stirred by a mixing spoon. The scene was so striking that I pulled onto the shoulder and got out of my car for a better look. The flock paused for a moment, as if suspended, then swept downward, paused again, and suddenly reversed direction and climbed higher than before. At moments there were cross-swirls and vortexes, like dust-devils following a car on a dirt road. It was mesmerizing.
Then I noticed a larger object plummeting through the starlings: a hawk. It attacked like a barracuda in a school of minnows. To avoid the hawk the flock morphed into a shape like a donut, with the predator passing through the hole. The hawk turned and climbed, dived again, and the flock turned to avoid it, forming other graceful, spiral-like shapes.
What makes congregations of this sort stay together? How can birds in a flock or fish in a school make what appear to be simultaneous turns, dives, and swoops without the individuals crashing into one another?
A theory popular a century ago, that a leader signals orders to the flock like a drum major to a marching band, was disproved when high-speed photography revealed that flocks constantly change leaders. More recent studies have focused on mathematical chaos theory, an approach pioneered by zoologist Frank Heppner. Heppner’s computer programs animated figures on a screen to represent birds, their motion duplicating the actual flight behavior of flocking birds.
Software engineer Craig Reynolds designed a more complex computer model using what he called "Boids" to simulate flocking synchronism. Reynolds’ “Boids” exhibited such lifelike behavior that they’ve been put to use in Hollywood movies — to duplicate a swarm of bats, for instance, in Tim Burton’s Batman Returns.
Of course there's another side to all of this. We can consider the scientific explanations — position and velocity, stimuli and responses, binary codes of behavior, the need for individuals in a flock to remain close enough together to be safe from predators but far enough apart to avoid injury — and it helps us to understand the world, in the sense that it’s probably biology we’re seeing, not bewitchment or the gods idly stirring swizzle sticks.
We're reminded that the world is an unfolding story and that now and then we can pull off the highway and take a minute to watch.
Photo of starling by Alden Chadwick
Most people know that “murmuration” is a collective noun designating a group of animals. What is less known is that it goes back centuries, to an era when European aristocrats used language to distance themselves from the common herd.
Some collective nouns came into use in the fourteenth and fifteenth centuries as “terms of venery” used by hunters. Rattling them off was a mark of erudition. The Book of Saint Albans, first published in 1486, included such terms a “gaggle” of geese, a “mob” of deer, a “covey” of grouse, a “bevy” of quail, a “fall” of woodcock, and a “sounder” of wild boar.
People other than hunters were likely to mention a “pride” of lions, a “cowardice” of curs, an “exultation” of larks, and a “murder” of crows. Other terms were meant to be humorous: a “blush” of boys, a “hastiness” of cooks, a “pity” of prisoners, a “drunkship” of cobblers, and a “melody” of harpists.
For starlings there were two terms: a “chattering” and a “murmuration.” If you’ve ever been near a flock of starlings roosting in a tree or strung along a telephone line, you know they’re vocal. They squeal. They grunt. Sometimes they chuckle. But mostly they murmur.
In nature, sometimes, everything fits. But seen another way it’s pure chaos. In our search for synthesis in the world we notice patterns that when seen from a distance appear orderly. Photograph a leaf in extreme close-up and it passes for abstract art. Zoom out far enough and our sun is one star in a vast, swirling galaxy of stars.
Stars are stipples. Starlings in a flock are stipples. The guy who released the first starlings into Central Park was a stipple. So are you and I.
That day, standing on the side of the highway watching that flock of starlings make fluid swoops in the distance, I glimpsed the face of a young woman as she drove past, heard the blare of a horn, noticed that trucks as they passed created flurries of wind that rocked my car on its suspension. It occurred to me that our lives are made of moments that cluster together, like flocks. If we step back far enough we can sometimes see a pattern, and sometimes it’s beautiful.This post is adapted from A Walk in the Animal Kingdom: Essays on Animals Wild and Tame, by Jerry Dennis, with illustrations by Glenn Wolff. Jerry Dennis is the author of The Living Great Lakes, It’s Raining Frogs and Fishes, The Bird in the Waterfall, and many other books. Visit him at www.JerryDennis.net.