10 Fun Facts About the Chimney Swift

In lots of cities east of the Rocky Mountains, the chattering calls of Chimney Swifts are as a lot part of summer season’s soundtrack because the cha-cha of sprinklers or ice cream truck jingles. Swifts minimize a singular profile typically described as resembling a cigar with wings, however that’s removed from the one factor that units them aside.

From their uncommon anatomy to their nesting conduct, Chimney Swifts are among the many strangest of our frequent avian species. The extra you study these fascinating birds, the extra seemingly you might be to develop into a hardcore, um, Swiftie. 

1. Chimney Swifts are amongst our most city birds. As their identify suggests, they nest in chimneys or deserted buildings, and also you’re almost certainly to seek out them in cities and cities with loads of such locations to take shelter. It’s a sample that started after European settlers constructed chimneys and different engaging nest websites throughout the panorama—together with wells, barns, silos, and outhouses—producing a inhabitants increase for swifts.

2. However it wasn’t at all times so. Earlier than settlers minimize down old-growth forests, swifts nested primarily in hole timber. In his Ornithological Biography, written within the 1830s, John James Audubon vividly described a large hollowed-out sycamore close to Louisville, Kentucky, the place, some 20 years earlier, he discovered what he estimated have been 9,000 swifts roosting. Audubon was there one morning when the birds started to exit the roost, and he “listened in amazement to the noise inside, which I might examine to nothing else than the sound of a big wheel revolving below a robust stream.”

3. As of late Chimney Swifts rely closely on people to supply nesting and roosting websites, however their historic reference to timber lives on. Lately hundreds of swifts have taken shelter throughout fall migration within the Davie Poplar, a virtually 400-year-old, partially hole tree on the campus of the College of North Carolina at Chapel Hill. Swifts additionally reportedly make use of hole, old-growth timber within the Amazon rainforest, together with chimneys and different human-built constructions.

4. Past that, not a lot is thought concerning the species in its nonbreeding territory, which incorporates components of Brazil, Chile, Ecuador, and Peru. Scientists say there’s an actual want for extra analysis to raised perceive this portion of Chimney Swifts’ life cycles, particularly since populations have plunged by greater than 50 % over the previous 50 years, in response to the 2025 State of the Birds report.

5. If Chimney Swifts stay in your space, it is best to be capable of discover them—simply search for. These aerial specialists spend practically all their waking hours on the wing, the place they may catch greater than 1,000 flies, beetles, and different bugs in a single day. In addition they drink water and bathe whereas in flight by swooping right down to a water physique’s floor. Due to swifts’ brisk, fluttering flight patterns, folks typically confuse them with bats.

6. Often Chimney Swifts even copulate on the wing, scientists imagine, although they extra sometimes mate on the nest web site. Throughout courtship, pairs carry out a show flight—a bonding conduct that continues into autumn—through which they snap their wings upward to kind a V form. One other courtship conduct entails small teams of swifts chasing each other, throughout which the species reaches a few of its highest flight speeds, which might exceed 60 miles per hour.

7. Once they’re not in flight, Chimney Swifts are sometimes hanging out, fairly actually. Their tiny toes weren’t constructed for perching—swifts should not recognized to land, stroll, or hop on horizontal surfaces—and as a substitute have 4 grappling-hook-like claws that assist them cling to vertical surfaces. Like woodpeckers, additionally they use their stiff tail feathers to prop them whereas upright.

8. Chimney Swifts have a particular instrument for constructing nests: their spit. When the birds arrive at their breeding grounds, sometimes in March or April, they kind pairs and discover a chimney or different appropriate web site to lift their younger. They piece collectively a nest from twigs, holding it collectively and affixing it to the wall with their glue-like saliva, produced by glands below their tongues that get bigger throughout breeding season. Females lay 4 or 5 pure-white eggs, which, with luck, hatch about 20 days later.

9. Throughout migration, vigilant birders can witness an incredible spectacle. At nightfall, hundreds of swifts kind an avian vortex as they swirl downward and dive headfirst right into a chimney to roost. As soon as inside, they rapidly flip to face upward and cling to a wall. The identical factor occurs on a smaller scale throughout nesting season, which could give the impression that the birds have shaped a breeding colony. In truth, sometimes solely a single pair will nest in any given chimney, however they’re typically joined by dozens of unpaired swifts. When the mercury drops, swifts discover heat in numbers. Their physique warmth has been recognized to maintain a chimney as much as 70 levels Fahrenheit hotter than the temperature exterior.

10. The shut connection between people and Chimney Swifts provides alternatives for folks to get entangled in defending the birds. Chimney constructions aren’t as frequent as they as soon as have been, and plenty of current chimneys have been capped, blocking swifts from entry. However Audubon chapters and different teams across the birds’ vary are working to maintain chimneys obtainable for birds and to build towers that function good substitutes. (Discover some helpful ideas here.) Others host Swift Evening Out occasions, inviting the general public to depend the birds as they swirl into chimneys and to study what they will do to guard these fascinating aerial acrobats.