1 Million Tree Swallows Prepare For Connecticut's Annual ‘Avian Ballet’

Sep 18, 2017

From late August to early October, as many as a million tree swallows gather on a small island near the mouth of the Connecticut River. Every evening at sunset they perform an “avian ballet” that has been called one of the “most astounding natural phenomena in the North American bird world.”

Andy Griswold, the director of the EcoTravel program at the Connecticut Audubon Society, says they try to keep the island where the swallows gather a bit under wraps.

“We generally don’t give out the name, just to discourage people from going in and disturbing them…It is a bit of a secret.”

The name may be a secret, but the island itself is well-known to local bird lovers. Some come every year to see this massive gathering of tree swallows – small, blue-green birds with black wings and white bellies.

The only way to see this special gathering is by boat. The RiverQuest, a 64-foot cruise boat, owned and run by Mindy and Mark Yuknat, is one of them.

The Yuknats know the tree swallows very well.

“I think we’ve been doing tree swallow cruises for 15 years,” said Mindy.

The RiverQuest heads out to the island. It doesn’t look like much, just covered in tall reeds.

But then, just as the sun begins to set, the tree swallows start coming in from every direction. Mindy says some of them have traveled as far as fifty miles to roost here for the night.

“We’ve got some coming in bit by bit. Now, they’re coming in right above us,” says Mindy.

They look like pepper in the sky above our heads, swarming towards the group that is forming above the island. Hundreds of thousands of them.

With a pair of binoculars, you can see them coming together into a ball, swirling above the island. Performing this so-called “ballet.”

Then, they start diving into the reeds, one group at a time. Mindy says they’re looking for a place to settle in for the night. The swirling ball starts to thin out, until all of a sudden the sky is empty.

Mindy says, “I’d say that we’re done. Good job, birds!”

Mindy says their performance is never the same, but tonight it lasted about twenty minutes before all the swallows found a place to sleep.

The birds gather like this because they want safety in numbers.

“If you’ve got a half million of your buddies joining you at your rest site for the night, um, your odds are much better that you won’t fall victim to a predator,” Andy says.

He says the birds will hang out here through September and the beginning of October to feed and build up body fat before they start their three-month journey to the Carolinas or the Gulf Coast.

“They’re basically waiting for northwest winds, to take advantage of a tail wind, makes their migration a lot easier, less calorie expenditure,” says Andy.

You still have a couple more weeks to see them, but if you miss them this year, don’t worry. They’ll be performing again next August, as they have for the last thirty years.