Chimney Swift Migration Is Full of Mysteries—but Rehabbed Birds Could Spill the Species’ Secrets

At nightfall in August 2025, a gaggle gathered within the parking zone of Housatonic Valley Regional Excessive College in Connecticut to look at the sky fill with a flurry of birds, their cigar-shaped our bodies dipping and swirling across the faculty’s chimney. Sunny Kellner, wildlife rehabilitation supervisor for the Sharon Audubon Center, held a Chimney Swift in her gloved hand, then launched it to hitch the dwelling vortex.

Kellner and her employees had labored tirelessly to take care of this creature—as they do every year for dozens of swifts whose nests equally fall to the bottom. “Folks all the time ask, ‘How are you aware the birds that you simply rehab survive?’” Kellner says. Her group has now got down to get a solution. The middle labored with Audubon biologists to tag rehabbed swifts with radio transmitters, hoping to learn the way their sufferers fare and perceive extra in regards to the species’ habits. “There are a complete lot of query marks that comply with that little swift up into the air,” says Eileen Fielding, Sharon Audubon Middle director.

Chimney Swifts are aerial insectivores that spend most of every day in flight. With brief, robust legs and forward-facing claws, they perch and nest vertically—up to now, in hole timber; right this moment, primarily in chimneys. However what occurs to the species exterior the breeding season is a thriller, says Alicia Brunner, who manages Audubon’s Migratory Fowl Monitoring Program. As they migrate from the jap United States to the higher Amazon Basin, their stopover habitats stay largely unknown.

The species’ populations have struggled in current many years as a consequence of insect declines, lack of nesting websites, and local weather change. Studying extra about Chimney Swifts’ full annual cycle may assist conservationists higher help them, however the birds are troublesome to seize and tag within the wild, Brunner says.

Rehabilitated swifts supply uncommon entry. The Sharon Audubon Middle takes in between 60 and 100 child swifts every summer season. As temperatures and humidity rise beginning in July, Chimney Swifts’ cup-shaped nests—manufactured from interwoven twigs glued along with dad and mom’ ropy saliva—face a better danger of falling.

On the middle, flightless and debilitated chicks recuperate in incubators or small mesh enclosures. As soon as they’ll take flight, the birds transfer to a big out of doors aviary outfitted with a makeshift chimney. For greater than 14 hours a day, rotating shifts of employees and volunteers feed the birds dwelling mealworms. “You don’t have an off minute,” says Kurt Johnson, a science trainer at Housatonic Valley Regional Excessive College who has volunteered up to now. “It’s a whole labor of affection.”

Final summer season, Brunner’s group joined this whirlwind to suit 20 birds with tiny radio tags. The group additionally put in a short lived Motus telemetry receiver on the faculty staging web site to trace the tagged birds as they left for migration. Researchers will know anytime these swifts come near a Motus station on their hemispheric journeys, although fewer exist in Latin America in comparison with the USA. After leaving Connecticut within the fall, two rehabbed birds had been picked up by the Motus community. They had been final detected in western Pennsylvania and South Carolina.

For the reason that tags’ batteries final a few yr, Brunner hopes to get extra knowledge this spring because the birds return. She is weighing different potential initiatives to maintain finding out Chimney Swifts, whether or not that’s tagging wild swifts for comparability, utilizing barometric strain tags to detect how excessive the species flies throughout migration, and even understanding whether or not birds return to the identical chimneys yr after yr. “Something we study them is actually actually thrilling,” she says. The swift rescuers in Connecticut, in the meantime, will likely be blissful if they’ll study that their sufferers returned, secure and sound.

This story initially ran within the Spring 2026 problem as “New Launch.” To obtain our print journal, turn out to be a member by making a donation today.