From a high vantage point, Chimney Swifts can sometimes be seen at eye level.
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It was a very strange inquiry: “Why are all those bats flying around in the middle of the day right over the center of town?” Right, very strange! Bats are primarily nocturnal, although they can be seen sometimes at dusk, and they are not likely to be seen flying high over developed areas with buildings and paved streets, for they search for insects over fields and grassy areas where their prey is more likely to be found, and not in the middle of the day in any event.
While not being present to observe what the questioner was seeing, it is probably safe to assume the “bats” were actually Chimney Swifts. With their small size and stiff winged, jerky flight, marginally similar to bats, it would be easy to see how one could mistake Chimney Swifts for bats.
Often described as flying “cigars with wings,” Chimney Swifts (left) spend virtually their entire day in the air feeding, catching insects with an unusually large mouth considering the size of the bird (right). The only swift in the east (there are three different species in the western United States), the Chimney Swift is incapable of perching, and can only cling to rough surfaces, most commonly found on the interior of brick or masonry chimneys where the swifts often congregate in large numbers.
In addition to their feet adapted for clinging, the Chimney Swift has tail spikes which help it in its clinging posture. The spikes are clearly visible in photo (left, click for larger version). Chimney Swifts actually nest in chimneys which undoubtedly accounts for their more commonly being found in cities and towns where chimneys are more likely to be found. They also are summer residents only, which, of course, is the time of year when chimneys are not typically belching out lots of smoke for winter heating purposes. For an internet photo of a Chimney Swift nest and babies, see: www.dilabiobirding.ca/images/backyard_2008-07_0388_ChimneySwiftBabies_W600.jpg.
Most commonly Chimney Swifts are seen high overhead and are best identified by their unique body shape and long wings, as seen in the photo (below right). But sometimes, if seen from a high vantage point such as we found on the Poughkeepsie, NY, Walkway across the Hudson River (walkway.org/), Chimney Swifts can be seen at eye level against a mountain side background (top of page).
In late summer when Chimney Swifts gather to begin their south bound migration to north-western South America (Columbia, Ecuador, Peru, and north-western Brazil) https://www.allaboutbirds.org/guide/Chimney_Swift/lifehistory, they congregate in large numbers at favoritechimneys such as this one in Kintnersville, PA, not far from our Pennsylvania home. (photo below) In past years, Jewel and I have witnessed thousands of Chimney Swifts coming into their chimney roosting place. They form into a funnel from a large circle high above the chimney, not unlike the “murmuration” pattern we have seen Tree Swallows use in Florida. See stlucieaudubon.org/hartBeat/hb2012/hb120301murmur.html. They then drop down into a tight double circular pattern that resembled a figure eight just above the chimney opening, creating two streams on opposite sides finally flowing into the chimney. The whole procedure is accomplished in a matter of 15 to 20 minutes, and it is virtually dark when the last Swifts enter their nightly roosting spot. I have not found any video of such a scene taking place inside the chimney, but, if ever documented, it undoubtedly would make spectacular viewing.
I made two trips this past August and early September, the prime time for this epic saga to occur, but alas, either missed the height of the migration gathering, or the Swifts have found a more preferable chimney. I estimated approximately three hundred Chimney Swifts gathering at the chimney and took some disappointing photos of them entering the chimney just before dark. (photo 7) I also took a video of the last nine minutes of the roosting procedure, which occurred when it was almost completely dark. The video, in which I have greatly increased the exposure so the birds can be seen, thereby creating an eerie pixelated cast to the video, can be found at: youtu.be/L0RkumMS63M (Warning, viewing this video may remind you of watching paint dry.)
Chimney Swifts do occur in Florida and we have seen them on St Lucie Audubon field trips in April. They may have been migratory birds though, for the 1992 Florida Breeding Bird Atlas recorded only a handful of breeding locations for the species in St Lucie County. But clearly, wherever you may be in the summer in eastern North America, if you see “bats” flying around in the middle of the day over the center of town, do a double take and check to make sure: They are probably Chimney Swifts. And while they may resemble cigars with wings, you can bet they are “smoking” a lot of very pesky bugs and mosquitos.
For more on Chimney Swifts, see www.chimneyswifts.org/ and legacy.myfwc.com/bba/docs/bba_chsw.pdf. For a photo of Chimney Swifts roosting in a chimney, see post.queensu.ca/~pearl/pics/Swiftpics/swiftsroosting.jpg.
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