Fall migration is a time of great movement: first-year birds freshly hatched and fledged and seasoned wayfinders making their way south to follow the food and avoid the cold.

Chimney Swift range map, courtesy of Cornell Lab of Ornithology / AllAboutBirds.org

One of the most entertaining and magnificent migrations is that of Chimney Swifts. This species makes a tremendous migration each spring and fall between South America (as far south as Chile) and North America (as far north as Saskatchewan in Canada). That is over 5,000 miles—a mighty feat for a bird that weighs no more than an ounce and has a wingspan of less than a foot!

But what draws most people’s attention to Chimney Swifts in the fall is their incredible roosting behavior. Chimney Swifts spend 90% of their lives flying—only pausing their lives on-the-wing to roost and to nest. They eat, sleep, and mate while flying. In migration, flocks of Chimney Swifts roost in—you guessed it—chimneys, clinging with their feet to the walls while they sleep.

And the way they enter the chimney is quite a sight.

As the sun sets, Chimney Swifts dart around the skies, catching any last insects to snack on before turning in for the night. Then just as sunset meets dusk, the swifts will form a swirling tornado of birds, circling above the chimney of their choice. One by one they drop into the chimney, sometimes in the hundreds or thousands, until suddenly the flock has entirely disappeared from sight, lining the walls of the chimney until dawn.

This phenomenon is the central “show” of Swift Night Out, a series of events held all over the country. Swift Night Out is a community and citizen science opportunity to gather, watch birds, ooh and ahh, and count the number of swifts using the chimney. This is both for fun and also benefits swift conservation as scientists monitor Chimney Swift populations throughout their range in the United States.

2023 Swift Night Out held at Cherokee Heights Middle School - cohosted by SoWBA, BIPOC Birding Club of Wisconsin and Feminist Bird Club - Madison, WI chapter. *Photo by Caitlyn Schuchhardt/Feminist Bird Club*

We have hosted Swift Night Out events in Madison with the Wisconsin Chimney Swift Working Group for over a decade. In 2023, we joined forces with the BIPOC Birding Club of Wisconsin and Feminist Bird Club - Madison, WI Chapter to put on even bigger and more fabulous Swift Night Out events, plus Swift Week events too. We continue that partnership each year now.

Part of the reason these events are held is to raise awareness about the declines in Chimney Swift populations. Chimney Swifts have declined in the US by nearly 70% since the 1960’s, and were listed as an Orange-Alert Tipping Point Species in the 2025 State of the Birds Report. This means their population has declined by over 50% in the last 50 years, and those declines have sped up in the last decade. As aerial insectivores which also rely on man-made structures to roost and nest, they’re vulnerable to many threats. Most significantly, pesticides reduce the availability of their food sources, and capped, metal-lined, or demolished chimneys eliminate their nesting and roosting sites.

To learn more about Chimney Swifts, check out this presentation by Dr. Steffanie Munguía that we and our partners hosted in August 2025 as part of the Mighty Migrations series!

2025 Swift Night Out and Swift Week summary

The Cherokee Heights Middle School chimney at sunset. *Photo by Birgit Bach*

In most years, Chimney Swifts use the large chimney at Cherokee Heights Middle School to roost. This chimney is critically important for swifts as it can house over 1500 swifts in one single night, night after night, during migration. (The chimney is slated to come down in the next couple of years, and we’re advocating for a faux chimney to be built to replace it — learn more here!)

This year, the swifts took up roosting sites in other locations around Madison, in smaller groups. This is not uncommon for Chimney Swifts — they seem to know of a variety of chimneys they can use, even if they’re smaller and can’t house quite as many as their primary and favored chimney. This tendency to “rotate chimneys” in some years is interesting. Are they switching it up to avoid predators? To maintain group knowledge of known habitat sites? Is their something else using their preferred chimney like a small army of raccoons? Is it that variety is the spice of life? These are questions with unknown answers, but worth considering.

You can find a roosting site near you following the instructions provided by the Wisconsin Chimney Swift Working Group (HERE).

Our Swift Night Out was cancelled because the site that swifts were using — Westminster Presbyterian Church — was too small to host a large group of people, especially with road construction in the area. However, we did host our smaller Swift Week events there. Groups of about 30 people met at Westminster each evening Sept. 7-13 and watched flocks of about 250 swifts come into roost. It is such a fun way to learn about this species, meet other bird enthusiasts, and enjoy the magic of migration.

Huge thank you goes out to Westminster Presbyterian Church for allowing us to camp out on their lawn for a couple of hours each evening!

A group of people watch the Chimney Swifts come into roost on Sept. 9 at Westmister Presbyterian Church. *Photo by Caitlyn Schuchhardt/Feminist Bird Club*

You can help Chimney Swifts!

There are a few things you can do to help Chimney Swifts in your own home and community (much of this information is provided by Birds Canada):

Learn about how you can support the faux chimney project at Cherokee Heights Middle School. This chimney is one of the largest and most important sites in Wisconsin and throughout their entire migration route!
If you have a home with a chimney:
- Avoid capping masonry chimney, or remove the cap between late April and October when chimney swifts are nesting or migrating (unless there is a metal liner, in which case your chimney is not swift-accessible).
- Close your damper to prevent nestlings from falling into the fireplace. This also acts as a sound barrier to minimize disturbance to nesting swifts.
- Routine chimney sweeping in April is important for maintaining good habitat before the nesting season. Dirty chimneys can cause nests and their contents (eggs and chicks!) to slip and fall off the wall.
- Chimney caps are designed for easy removal. Chimneys should be inspected and cleaned at least once per year to prevent dangerous buildup of soot or creosote. Cap removal/installation can be scheduled at the same time as the homeowner’s chimney inspection and cleaning.
Advocate for schools and churches to maintain their chimneys with Chimney Swifts in mind. These large chimneys are often excellent habitat for these birds!
Purchase a Swift Night Out t-shirt from our store. All of the proceeds from those shirts go toward the faux chimney project at Cherokee Heights Middle School.