In The Bay, Gilbert Klingel writes that dividing a day into the hours of events in a marsh is a better way of keeping time than going by the clock. "How much more descriptive it is to speak of the Dark Hour of the First Voice, the Time of the Wakening of the Birds, the Interval of the Rising Tide, or the Hour of the Littorina!" Klingel exclaims. "The creatures of the swamp do not live by arithmetic; they are moved by events, are actuated by sun and tide, by light and darkness, by heat and cold, by hunger and fullness, and by the movements of life about them."
Klingel's remarks come to mind when I think of the swallows in Constitution Island Marsh Sanctuary in Phillipstown, N.Y. Owned by the Taconic State Park Commission and administered by the National Audubon Society, the sanctuary is located 50 miles up the Hudson River from Manhattan and directly across from West Point. Here, in August and September before migration, dusk is the Hour of the Swallows. From nearby lakes and ponds where they have spent the day, thousands of them fly in to frolic and to roost in the 270-acre tidal marsh. The swallows are present in such abundance I can see them from my house a mile away, but for sheer spectacle nothing can possibly match being right there in the marsh with them. It's like being in the midst of a feathered blizzard.
Just before Labor Day the tides were right for getting a canoe over the mud flats to the heart of the action, and I spent three consecutive evenings watching the birds at close range with Dave Seymour, a friend who manages the sanctuary. By the time we paddled to the creek bend where the birds concentrate, there were swallows everywhere—the majority were tree swallows, the rest bank, rough-winged and barn swallows. They were flying in over the stands of cattails and wild rice and dipping into the flat water of the creek before bouncing into the air again like skipped stones. On both sides of us, the birds whipped the water white. There were swallows directly overhead; and above them more swallows, and still more above them. "I've never been bombed yet," Seymour said. "They must know I'm from Audubon." Through my binoculars I could see swallows stacked up in the sky until they disappeared into the bright belly of a cloud lit by the setting sun. A few birds began to roost, fluttering for footholds on the head of a cattail or bending down the delicate stalks of wild rice. The swallows, amid the traceries of green, gave the scene the aspect of an exquisite Chinese painting.
The buildup of swallows continued. It didn't seem possible that they could fly without colliding with one another. By now the tide was dropping quickly, and as we paddled out, a couple of thousand screeching blackbirds took off in alarm from the trees on the south dike. We stopped, and we saw still more swallows flying in over the dike to the marsh. I began to count those flying through a 50-foot gap between two trees. In a minute I counted 200, and given the length of the dike, I calculated that 5,000 to 6,000 swallows a minute were pouring into the marsh from this direction alone. Even if I trimmed that to 1,000 swallows a minute from all directions, the number was extraordinary. "Look back," said Seymour. I looked toward the creek bend. The air was thick with swallows as low and as high as we could see. Conservatively, we both estimated there were 10,000 to 20,000 swallows flying. There might well have been more. Flocks upward of 100,000 have been seen migrating along the East Coast.
The next night there were more, and on the third night, when we brought our wives, there were even more. This time, just before darkness closed in, the swallows did something I had heard about but had never seen. Suddenly with a rush, all the birds that had gone to roost in the marsh rose up 20 feet. As though one, they massed together in a smoky band and spiraled into the sky. The swallows flew higher and higher, twisting and turning like a giant scarf. Then slowly the formation tore in half like gauze, and there were two giant scarves climbing into the clouds. We lost them, even with binoculars. Five minutes passed. We could see them in flocks of 20, 50 and more flying low, returning to the roost in the last pinch of light. We looked up in the sky a final time. Not a single bird was to be seen. We paddled out. The Hour of the Swallows was over.