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Dazzling Purple Martin Display at Nimisila Metro Park Marks the Season's Passing

canoes at sunset
Dozens of bird watchers gather on Nimisila Reservoir to watch the nightly roosting display of migrating purple martins.

The rhythms of nature continue despite the disruptions the pandemic has caused our lives.

In southern Summit County, the season’s change is marked by a dazzling display of migrating birds. Each night bird watchers flock to witness the mass gathering of purple martins on Nimisila Reservoir.

It’s early September, a warm evening just before sunset. Dozens of bird watchers gather on shore, poised with spotting scopes and binoculars. But the best viewing is out on the water.

At least three dozen kayaks, canoes and paddleboards float near a reed-covered sandbar in the middle of Nimisila Reservoir, the largest of the Portage Lakes just south of Akron, waiting for the show to begin.

It starts with a few scimitar-shaped birds overhead, speeding in intersecting blurs as the sun dips toward the horizon.

They’re purple martins, the largest of America’s swallow species, iridescent blue and built for flying.

Summit Metro Parks naturalists Janean Kazimir, left, and Sarah Graham, right, paddle on Nimisila Reservoir to watch the migration display of the local purple martin population.

Summit Metro Parks naturalists and Sarah Graham are along this evening to offer insight into the aerial display.

Kazimir said the birds are drawn to the remoteness of the reed bed.

“They decided it’s a great place to roost at night because there are no predators. They’re completely safe from raccoons, foxes and anything that might try to come and get them,” she said.

Graham tries to put an estimate on the growing hoard of birds overhead.

“There’s around 10,000, but toward the end of the first week of September, we’ll see less and less as they migrate out,” she said.

She said each night they return to this suburban lake from as far as 20 miles away, massing together before flying 4,000 miles to Brazil where they spend the winter feeding in the rainforest.

Seeking a safe roost

As twilight approaches the pace of the swirling flock increases. A few birds alight briefly, sampling the security of the roost before fluttering back into the air.

The park district placed buoys around the reed bed, which Kazimir said marks a safe distance for viewing.

“The moment they do not feel safe anymore they’re going to take off,” she said.

She said the birds can be skittish.

“In some years we’ve had an owl come in and scare them away. We’ve also had folks disregard the buoys and start paddling through those areas,” Kazimir said. 

Owls aren’t the only potential predators. Nimisila is home to a pair of bald eagles and four osprey nests.

But nothing can catch a careening purple martin. Like all swallows, with their forked tails and streamlined wings, they’re masters of the air.

As darkness creeped in, the martins form a fast-moving vortex, a synchronized aerial ballet.


“Folks have studied this mathematically, and it turns out they are influenced by the six birds around them. So if one decides to turn to the right there’s this cascade, almost like folks at a baseball game doing the wave,” Kazimir said.

The birds skim inches above the water, surrounding us like a scene from Hitchcock, without the terror. In fact, it’s thrilling to witness. Clouds of purple martins drop into the reeds, wave after wave. And then suddenly they’re gone. There's not a bird in the sky as night embraces Nimisila, and the paddlers head to shore.

A farewell to summer

That's where I met Bill York and Tim Millikan, still aglow from the sunset display.

“It was gorgeous,” York said. "The sky was filled with so many birds, as far as you could see above you.”

“And then you hear all the air from their wings, thousands of them,” Millikan said.

Some local birders use weather radar to monitor the purple martin flock. It shows the numbers at Nimisila growing steadily throughout August, coalescing and dispersing each day in a steady rhythm.

Then, the radar shows a blob of birds streaming south.

The roosting birds on the pristine lake end the season in a flurry of activity, then just as suddenly, like summer itself, they’re gone until next year.

Jeff is your average chemist turned radio host and reporter. He currently hosts middays on WKSU and has reported extensively on science, politics, business, and the environment.