Tuesday, October 17, 2017

"Murmuration of Swallows"

Sydney M. Williams

Essay from Essex
“Murmuration of Swallows”
October 17, 2017

True hope is swift, and flies with swallow’s wings.”
                                                                                                William Shakespeare (1564-1616)
                                                                                                Richard III, Act 5, Scene 2 – 1592

They began to arrive a few minutes before dusk – a few singly, many in small groups, groups that become larger as the sun sank toward the horizon. Soon the darkening sky was laden with tens of thousands of (mostly) tree swallows that swept and dove in unison, first in one direction, then in another – their sonar infallible, as they flew inches apart at speeds of up to forty miles per hour. Then, they circled and twirled earthward, at ever increasing speeds, in tornado-like formation, to the grasses on Goose Island, just off the coast of Old Lyme, in the Connecticut River.

What we witnessed was one of nature’s magical moments. Ornithologists know why swallows stop to feed – to bulk up for long migrations south. They understand why they congregate in ‘flights.’ There is safety in numbers, against peregrine falcons, red-tailed hawks and other predators. Naturalists know that, because of dense stands of Phragmites, Goose Island is relatively predator free. They also realize that the Connecticut River’s estuary offers, for feeding purposes, a high-density population of crepuscular insects. But scientists don’t know how their sonar works – what allows them fly in close formation and to simultaneously change direction without colliding.

Around the world there are more than eighty types of swallows, with Africa carrying the largest variety. They are common throughout North America, with tree, barn, cave, cliff and bank among the best known. They, along with martins, belong to the family of Passerine birds, which are known for aerial feeding.

Murmuration describes the phenomenon of birds flying in close formation, swooping first one way and then another, in perfect synchronization. The word derives from Middle English, the act of murmuring – the utterance of low, continuous sounds, or complaining noises. Listening carefully, as we watched them gather and circle before their descent, the noise was detectable. Swallows are not alone in their ability to fly in synchronized fashion. Starlings, often seen as one of nature’s least loved birds, are known for their aerial, spectaculars – again, mostly to avoid predators, like falcons or hawks. It is difficult for a bird of prey to single out an individual starling or swallow, when the group is moving in unison, inches apart. Keep in mind, as well, flocking birds are not idle. To borrow a phrase, they eat on the fly. They roost to rest. Scientists have determined that individual starlings are able to consistently coordinate with their seven nearest neighbors, yet how hundreds collectively correlate such movements, while flying wingtip-to-wingtip, remains a mystery.

The Connecticut River estuary is not the only place where swallows perform these acrobatics. They can be seen in the fall in England, before flying 3500 miles to South Africa. Floridians see them in the spring, before they make their way north. Like most living things, swallows are creatures of habit. For many years, cliff swallows summered at the Mission in San Juan Capistrano, California, building nests in the old, stone church. For eighty years, their return had been celebrated on March 19. Then, in the 1990s, when workers removed their nests during restoration of the Mission, they were forced to find alternative accommodations, including a near-by housing project. Now, they are being wooed back, with fake nests and the playing of recorded vocalizations. This past spring a few mud nests began to appear. The celebration will continue.

The gathering – ours that is, not the swallows – was at a beautiful home, conveniently situated overlooking Goose Island, a few hundred yards offshore – all in the estuary of the Connecticut River – and no more than a couple of miles from where Roger Tory Peterson lived for over forty years. (In fact, the event was a fund-raiser for the Roger Tory Peterson Estuary Center, a Chapter of the Connecticut Audubon Society.)  Kayakers and other boaters could be seen positioning themselves, as they do each night when swallows descend to this small island, which they do for about a week – stuffing their bodies and conserving their strength – before continuing the long flight south. A high school string quartet played softly in the back ground, the music drifted through the evening air, as friends chatted, sipped wine and munched on passed hors d’oeuvres. All of us marveled at what we had witnessed. How lucky, I thought, we live in this place.

It is the job of scientists to seek answers. There is much for them to still learn; for example, nerve systems that allow birds their remarkable sonar. But for the rest of us, the beauty is in the mystery that remains unexplained – the fascination of watching, without comprehending, the murmuration of swallows. Nature is humbling. How does something we cannot explain – cannot even fathom – function? In this natural world with its beauty and complexities, there is room for both the artist and the scientist, each of whom, in their own way, seeks understanding. 

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