The Swallow Vortex

Summer has passed, winter approaches. All creatures turn their attention to survival, shelter, safe harbor. Each sunset at this time of year, hundreds of thousands of tree swallows are drawn to an island in the Connecticut River, to roost together among tall marsh grass. Now the breeding is done, the drive is to find safety in numbers.

The calm before the swallows descend upon their roost for the night. (Photo by Vanessa Mickan)

To start, you see one or two swallows, feathered darts overhead. Then as the light fades, the air begins to thicken with birds. They stream in low to the water, sometimes skimming the surface to sip a last drink for the night. They pour across the ridgelines, zigzagging randomly as they glean insects on the wing. The sound builds as they call to one another, racing toward their roosting place. 

The swallows stream in from all directions. (Photo by Vanessa Mickan)

It is chaos theory in action. These birds have spent the day dispersed across a wide area and have each flown their own erratic path to get here; now, in the space of minutes, they form an organized system. They start to fly in the same direction, swirling around and around above the island, forming not so much a flock as a meteorological event -- a whirlpool, a cloud, a tornado. No human word can quite sum it up, because this event is a mystery to the human senses. How do the birds communicate? How do they organize themselves? How do they know to do this?

  

Photo by Frank Gallo



Photo by Frank Gallo

Photo by Frank Gallo

Something happens. Some signal -- the amount of light? -- is picked up by the vortex, and with the suddenness of a summer thunderstorm, the birds rain down hard. The ones at the bottom of the funnel plummet headlong into the grass, seeming to drag the rest down with them. The sky drains within 40 seconds. It is as if it were a dream, a hallucination. Where just a moment ago, you were in the midst of a swirling mass of life and noise and movement, now before you is a quiet sky. It is as if nothing happened.

Photo by Frank Gallo

The birds' day is done. Within the grass, they are no doubt jostling for position, finding their places to sleep, settling down. And now it's your turn. You head for the dark highway and begin to follow the red tail lights of the stream of cars in front of you. Your path may wind and zigzag, but it is a thread in a lacework of paths that leads to the city or the township where you live, the place where you and others of your species gather to roost each night.

Photo by Vanessa Mickan

Photo by Vanessa Mickan