ON THE LOWER CONNECTICUT RIVER, Conn. (AP) — The first swallows appear at sunset, inky flecks in a dusky pink sky. A cloud of birds forms, then another and another. Soon the entire sky is teeming with tree swallows — hundreds of thousands of them — swooping and swirling and shimmying in a dazzling aerial ballet that paints the sky black.
Peering through binoculars from the river below, birders, boaters and tourists gasp.
But the swallows have only begun their nightly fall spectacular.
As if on cue, they form a long, streaky line. A momentary pause.
Suddenly they are falling, spiraling from the sky at speeds of up to 65 miles (105 kilometers) an hour in a dizzying, tornado-like funnel that, in a few breathtaking seconds, disappears into the reeds below.
For a short time the river is silent, except for the lapping of waves and cries of wonder from the boats.
Then another cloud of birds forms and repeats the performance. And another. The entire roosting ritual lasts about 20 minutes every night from late August to early October. Audubon Society experts and others estimate that it draws up to 400,000 birds.
When it is over, the river is dark except for the lights of the boats.
The reeds are dense and silent. The colony of swallows is asleep for the night.
As their vessels glide home in the moonlight, mesmerized viewers are left to ponder the mystery and magic of what they have witnessed.
"This is undoubtedly one of the most astounding natural phenomenons in the bird world that you can experience in North America," says Milan Bull, senior director of science and conservation at the Connecticut Audubon Society. "It's more remarkable than the sandhill crane migration on the Platte River (in Nebraska), the snow goose migration in the Arctic and the hawk migration in the fall."
It's also more mysterious.
No one really understands why these dynamic little birds with their metallic blue-green feathers and white bellies, descend nightly on a small island on the lower Connecticut River in preparation for their long migration south. According to the Connecticut Audubon Society, the only other known location where swallows gather in such numbers is in southeastern Louisiana, where they plummet into sugarcane fields to roost. Smaller flocks have also been seen in Cape May, New Jersey.
"The mystery is one of the reasons the tree swallow is such a charismatic bird," says Andy Griswold of the Connecticut Audubon Society, who is a seasonal swallow guide on the river. "There are lots of theories of course, but we really don't know why they choose this spot or why they form tornadoes."
Safety in numbers is one theory. The swallows, whom experts speculate come from as far as 40 miles (64 kilometers) away, are far less likely to be killed by predators such as falcons and eagles when they mass in a blizzard-like cloud. The reeds in which they roost — called phragmites — are thick and invasive and almost impossible for predators to penetrate.
Until about 14 years ago, only birders and locals knew much about the phenomenon. Then a local couple, Mark and Mindy Yuknat, teamed up with the Connecticut Audubon Society to host "swallow cruises" on their 64-foot (19-meter) catamaran, RiverQuest. The boat, which seats about 50 people, ferries visitors from the dock at Haddam — opposite the historic Goodspeed Opera House — about 45 minutes downriver.
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