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Swiftly Flying Birds

Updated: Sep 28, 2023

Last week MAS sponsored two opportunites to watch migrating Chimney Swifts go to roost in the East Mecklenburg Hight School Chimney. Many of you were part of the 75+ folks who turned out for the events. For those were not able to join us here is some information about these fascinating birds.

Chimney swift flying

The small, agile, fast-flying Chimney Swift is readily identified by its characteristic "flying cigar" profile. The gray-brown plumage of these 5-6 inches birds can be recognized by their stiff wing flight pattern. Members of this family are among the fastest fliers in the bird world, spending all of their daylight hours on the wing and coming down to rest only at night because they rely exclusively on flying insects for food.

Hundreds of Chimney swifts roosting on the side of a tree

The Chimney Swift was named after its habit of nesting and resting inside of chimneys. Until the European settlement of North America, Chimney Swifts nested in hollow trees. Now, they have adapted to urbanization and prefer nesting in chimneys and other artificial sites, including air vents, garages, silos and barns. They are known to breed from southern Canada east of Saskatchewan, south through Texas and to the Atlantic seaboard. They migrate to northern South American in the fall.

Because of the Chimney Swift’s nesting habits, they can be easily captured and banded in such situations. Hence, it has been studied much more thoroughly than other North American swifts. In late summer, hundreds or even thousands of individuals may roost in one large chimney, gathering in spectacular flocks overhead at dusk.

In recent years swift nesting it has become increasingly difficult to witness this spectaclel in the Charlotte area because of the lack of suitable nesting sites. People are capping chimneys or building them with slick surfaces the birds can’t hold on to. In addition many of the large ‘commercial’ type chimneys found at older schools and warehouses are being torn down. Audubon encourages citizens to leave chimneys uncapped during swift nesting season from early April through mid to late summer.

Chimney swift clinging to a fence post

Fast facts about Chimney Swifts

  • Swifts are more closely related to hummingbirds than any other groups of birds, even swallows which they resemble. Swifts and hummingbirds make up an Order of birds called Apodiformes. The prefix ‘apodi’ means ‘no feet’. Of cause these birds have feet but they are so tiny they can’t perch on a limb or walk like other birds. The feet are designed for clinging not perching.

  • Chimney Swifts do everything on the wing – eating, drinking, bathing; even snapping off twigs for nesting material. If they’re not sitting on their nest or roosting in a chimney, they are flying.

  • Swifts attach the sticks of their nests together with their spit, which basically glues the nest together and sticks it securely to the wall of the chimney.

Chimney swift nest inside of a chimney with 5 birds in it
  • Swifts toes are similar to our opposable thumbs – two of their four toes point backward, when they are in flight, and then swing forward for clinging to a tree or chimney. This toe arrangement is called “pamprodactyl.”

  • Large numbers of Chimney Swifts roost together in a single chimney during migration and the nonbreeding season. There’s warmth in numbers: during cold nights, the temperature inside a chimney roost can be 70°F warmer than outside.

  • Unmated swifts continue roosting together in the summer, sometimes in large groups. But the species does not nest colonially. You’ll find only one breeding pair nesting in any one chimney. The pair may tolerate other nonbreeders roosting in their chimney but there is only one nest.

  • The oldest Chimney Swift on record was at least 14 years old when it was captured and released by an Ohio bird bander in 1970.

Infographic: Chimney swifts eat 1/3 of their weight in insects everyday
Curtesy of Sassafras Audubon in Bloomington, IN


  • Chimney Swifts eat nearly one third of their own weight in flying insect pests such as mosquitoes, biting flies and termites every day.

  • Chimney Swifts historically used large, hollow trees for nests and roosts. As the ancient forests were cut down, they learned to use chimneys and other structures instead.

  • Today, just like Purple Martins, Chimney Swifts rely almost entirely on man-made structures for nest sites.

  • Because they cannot perch like songbirds, Chimney Swifts must have deep shafts in which to raise their families and roost at night.

  • Chimney Swifts are protected by State Wildlife Codes and Federal law under the Migratory Bird Treaty Act of 1916.

  • Like all Neotropical Migrants, Chimney Swifts are declining in numbers and need our assistance.

  • Like watching a beautiful sunset, the aesthetic value of observing Chimney Swifts’ aerial acrobatics and interactions is a simple pleasure nature has to offer.

Chimney swift nesting tower at Colonel Francis Beatty Park in Matthews, NC
Chimney swift nesting tower at Colonel Francis Beatty Park in Matthews, NC


  • If you have a masonry or clay flue-tile chimney, keep the top open and the damper closed from March through October to provide a nest site for these insect-eaters. Metal chimneys should be permanently capped to prevent birds and other wildlife from being trapped.

  • Have your chimney cleaned in early March before the Chimney Swifts return from their winter home n South America.

  • Work with local conservation groups to construct Chimney Swift Towers and educate your friends and neighbors about Chimney Swifts.



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