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At dusk in August 2025, a group gathered in the parking lot of Housatonic Valley Regional High School in Connecticut to watch the sky fill with a flurry of birds, their cigar-shaped bodies dipping and swirling around the school’s chimney. Sunny Kellner, wildlife rehabilitation manager for the Sharon ̽����ѡ Center, held a Chimney Swift in her gloved hand, then released it to join the living vortex.

Kellner and her staff had worked tirelessly to care for this creature—as they do each year for dozens of swifts whose nests similarly fall to the ground. “People always ask, ‘How do you know the birds that you rehab survive?’” Kellner says. Her team has now set out to get an answer. The center worked with ̽����ѡ biologists to tag rehabbed swifts with radio transmitters, hoping to learn how their patients fare and understand more about the species’ behavior. “There are a whole lot of question marks that follow that little swift up into the air,” says Eileen Fielding, Sharon ̽����ѡ Center director.

Chimney Swifts are aerial insectivores that spend most of each day in flight. With short, strong legs and forward-facing claws, they perch and nest vertically—in the past, in hollow trees; today, mainly in chimneys. But what happens to the species outside the breeding season is a mystery, says Alicia Brunner, who manages ̽����ѡ’s Migratory Bird Tracking Program. As they migrate from the eastern United States to the upper Amazon Basin, their stopover habitats remain largely unknown.

The species’ populations have struggled in recent decades due to insect declines, loss of nesting sites, and climate change. Learning more about Chimney Swifts’ full annual cycle could help conservationists better support them, but the birds are difficult to capture and tag in the wild, Brunner says.

Rehabilitated swifts offer rare access. The Sharon ̽����ѡ Center takes in between 60 and 100 baby swifts each summer. As temperatures and humidity rise starting in July, Chimney Swifts’ cup-shaped nests—made of interwoven twigs glued together with parents’ ropy saliva—face a greater risk of falling.

At the center, flightless and debilitated chicks recover in incubators or small mesh enclosures. Once they can take flight, the birds move to a large outdoor aviary equipped with a makeshift chimney. For more than 14 hours a day, rotating shifts of staff and volunteers feed the birds living mealworms. “You don’t have an off minute,” says Kurt Johnson, a science teacher at Housatonic Valley Regional High School who has volunteered in the past. “It’s an entire labor of love.”

Last summer, Brunner’s team joined this whirlwind to fit 20 birds with tiny radio tags. The group also installed a temporary Motus telemetry receiver at the school staging site to track the tagged birds as they left for migration. Researchers will know anytime those swifts come close to a Motus station on their hemispheric journeys, though fewer exist in Latin America compared to the United States. After leaving Connecticut in the fall, two rehabbed birds were picked up by the Motus network. They were last detected in western Pennsylvania and South Carolina.

Since the tags’ batteries last about a year, Brunner hopes to get additional data this spring as the birds return. She is weighing other potential projects to keep studying Chimney Swifts, whether that’s tagging wild swifts for comparison, using barometric pressure tags to detect how high the species flies during migration, or even understanding whether birds return to the same chimneys year after year. “Anything we learn about them is honestly really exciting,” she says. The swift rescuers in Connecticut, meanwhile, will be happy if they can learn that their patients returned, safe and sound.

This story originally ran in the Spring 2026 issue as “New Release.” To receive our print magazine, become a member by .