Twice a year, Vaux’s Swifts migrate through the Willamette Valley. The little birds fly non-stop all day, gobbling up insects. When it’s time to roost for the night, they head to dismantled brick chimneys for warmth and safety. Thousands fill the sky, circling and chirping- before diving in. The phenomenon happens twice a year in Eugene.
It’s fall migration for the Vaux’s Swifts. These birds summered in Canada and now they are heading south to Mexico and beyond, with their offspring. One of their stops is here-- Agate Hall chimney on the University of Oregon campus. It’s the second largest roosting site in the state, after Chapman School chimneyin Portland.
“Typically, they’ll wait to enter the chimney until after sunset.” Maeve Sowles is President of the Audubon Society of Lane Countyand she’s watched the dance of the swifts for decades.
“They do just practically materialize out of thin air," she said. "Because they might fly up super high and then drop down. Almost like a swarm," she said.
Sowles said Vaux’s swifts are sensitive to cooler temperatures. And air pollution.
“The combination of the heavy smoke and the fires makes it hard for birds whose lungs are pretty sensitive to pollution," she said. "And also those who are hunting insects--they need to be able to find their insects and if they can’t eat, they won’t survive.”
These are forest birds. Sowles said they used to roost in huge snag trees but deforestation from old growth logging has forced them to adapt to using man made roosts like old chimneys.
Sowles said a few years ago, the university sent a hazmat team down to inspect the Agate Hall smokestack. She said the structure was deemed sound and they also cleaned out about 20 feet of bird poop, making room for more swifts to dive in and roost.
“It’s a phenomenon that is wonderful to watch and very exciting to see these little birds use the chimney in this way,” Sowles said.
Longtime Eugene resident William Kessler stood with other observers in a parking lot across from Hayward Field, his eyes skyward.
Reporter: “Have you ever seen this before?”
“No. First time,” he said still looking up.
The Vaux’s swifts tend to arrive here in late August and depart by late September.
“WOW! Ah look!"
