If all goes according to plan, Runnymede Park in Herndon will have nearly a thousand new residents next spring.
The nonprofit organization Friends of Runnymede Park just built a stand-alone chimney tower in hopes of attracting one of nature’s most unusual birds: the chimney swift.
The 14-foot tower is insulated and constructed to perfectly accommodate up to 1,000 of the tiny birds.
According to the National Audubon Society, chimney swifts are small gray birds with slender bodies and long, narrow, curved wings. They have round heads, short necks, and short, tapered tails. Their bills are wide and so short, they are often difficult to see.
“They have been in North America for longer than we have,” said FORP board member Dave Swan, who helped build the new chimney tower. “They nested in hollow trees before the European settlement of North America.
“In colonial days, the birds were called American swifts, but with the advent of residential growth across the country came the cutting down of the large, hollow, first-generation trees in which they lived. As trees went down, and homes went up across America, the birds adapted to living in chimneys, hence their current name.”
Swan said North American chimney swifts migrate to South America for the winter and return in May. “It is almost a perfect time frame for both the birds and homeowners” he said. “They stay away for the winter months when chimneys are being used by people, and return for the warmer months when they are not.”
According to Carol Hadlock, president of FORP, the birds also serve a useful purpose.
“They eat 30 percent of their body weight a day in mosquitoes, gnats and flies,” she said. “They spend all day long on the wing, flying and eating insects.”
Hadlock said part of the reason the birds stay airborne so long is they have an unusual anatomy that does not let them land or perch like other birds.
“Their feet are constructed in such a way that they cannot grasp horizontal surfaces,” she said. “They can only cling vertically — almost like a bat — to a surface, so they rarely, if ever, stop flying until it is time to go in for the night. Unlike bats, they are not nocturnal.”
Hadlock is a member of the National Audubon Society and since 2007, has organized a bird-watching event called Swift’s Night Out. She and other members target local area chimneys where the birds reside and watch their nightly ritual. She said hundreds, even thousands, of the birds often spend the night in one chimney.
“They circle a chimney, hundreds at a time, and then just dive down into it in formation,” she said. “They look like diving fighter planes or ‘flying cigars,’ as they are often called.”
FORP board member and former Herndon Mayor Carol Bruce said a flock of the birds used to reside near her home in Herndon before a local school capped its chimney.
“I remember, before the renovations at the middle school across from me, they used to roost in the chimney over there,” she said. “I used to love to watch them gather each evening, begin to circle, and then quickly drop in for the night. Now, as more and more chimneys are being capped, they are endangered once again. So, people are beginning to construct freestanding chimney towers like this one.”
According to the National Audubon Society, with more commercial chimneys capped, the chimney swift population in the U.S. has declined by more than 50 percent in the last 40 years. “New homes and buildings automatically get chimney caps these days, so there is not a lot of new opportunity for the birds to find new homes,” Swan said. “And that’s a shame because they are so beneficial. They eat all the insects that pester humans.”
Hadlock hopes the new Herndon tower will attract the birds to Runnymede Park come spring. “If they come, it will benefit everyone,” she said. “The birds will have their own home, and I can organize a Swift’s Night Out bird-watching event closer to my own home, instead of having to go out to Arlington or Loudoun County.”
The Friends of Runnymede Park will hold a ribbon-cutting ceremony for the new tower at 12:45 p.m Oct. 6.