What is a Chimney Swift?

Chimney Swifts are dark gray-brown, swallow-like birds with long, slightly curved wings and stubby tails. They fly with stiff, rapid wing beats. Their call while in flight is a series of quick, chittering noises. The swift’s nickname is a “flying cigar” because of its short 5.25” body and its 12.5” wingspan. This small bird spends almost its entire life in flight, feeding and drinking on the wing. Swifts help keep insect numbers in check and eat up to half their weight in flying insects each day! Chimney Swifts nest and roost in chimneys, concrete silos and in other enclosed vertical masonry.

Unfortunately, Chimney Swift populations are declining throughout North America. One reason for this decline may be that fewer chimneys remain uncapped and available as habitat. Our chimneys are their homes — they return to the same chimney each year and are dependent on us to provide nesting and roosting space.

Chimney Swifts circling a roosting chimney.
Photo by Joni Denker

A Swift Night Out Wisconsin

A Wisconsin-wide Citizen Science Event – Now Through the End of September

Swift Night Out is a continent-wide effort to raise awareness about Chimney Swifts and their roosting sites.  After swifts have finished raising their young, they gather in groups at communal roosting chimneys before beginning their fall migration to the upper Amazon basin of Peru, Ecuador, Chile, and Brazil.  For more info on the event history, see this page

This year, Madison Audubon and the Wisconsin Chimney Swift Working Group are partnering with Wisconsinites to count Chimney Swifts during evenings in September.  

You are invited to count Chimney Swifts at a roosting chimney, then submit results through eBird (preferred), or use a tracking form (see links and instructions below).  No experience is necessary.


COVID-19 Information:
Follow these guidelines to help increase your event’s safety during the COVID-19 pandemic: choose a site that provides adequate room to spread out; limit participants to a small group, such as your family or those living in your residence; wear masks if you can’t practice social distancing.

How to Host a Swift Night Out:

Click this link to download an easy guide on how to hold a Swift Night Out (SNO). 

  • Pick one or more nights from early August in northern Wisconsin through mid- to late September in southern Wisconsin.
  • Look for tall brick chimneys (or ones on homes) that are uncapped. Watch to see where swifts are feeding and congregating.
  • Observe the roost starting about 30 minutes before sunset until 10 minutes after the last swift enters the chimney. Count (or estimate) the number of swifts as they enter the chimney. It’s useful to count in groups of five or 10 birds at a time when many birds pour into the chimney in a short period of time.
  • Enter the data on eBird (preferred!). To get started with eBird: ebird-quick-start-guide. When prompted for location, map your roost site to an exact address or point. After you enter the number of Chimney Swifts, please use the hash tag #swiftwi in the Chimney Swift details section. This will help us greatly in accessing the data.
  • If you want to go above and beyond and be a ROCK STAR, please add additional information in the Chimney Swift details section, in this exact order, with semicolons separating the data: #swiftwi; the type of building (residence, school, church, business, hospital, apartment, swift tower/structure, etc.); the condition of the chimney (in good shape; in need of repair); any other notes. (Example: #swiftwi; residence; chimney in need of repair; any other notes)
  • Please also include any Common Nighthawks you see. These aerial insectivores are also in decline.
  • Or, if you do not use eBird, use this tracking form send the same information as above plus date of observation, exact start time, length of observation at the roost site, and your name, address, email address to Fred Dike, 2613 Waltham Rd., Madison, WI 53711; freddmadison@aol.com.

Bird in Hand
WI Humane Society

Swifts in Your Chimney?

Congratulations! It’s easy to be a swift landlord. Just keep the chimney clean and the fireplace damper closed. You likely will not have a problem with swifts entering the house from the fireplace. Occasionally, hard summer rains may loosen the nest from the masonry chimney, especially if there is a creosote buildup. If the nest falls onto the damper, or if the damper is open, you may find a nest or young chicks in the fireplace.

If this happens, contact a licensed wildlife rehabilitator to decide on the most appropriate action. In Wisconsin, refer to dnr.wi.gov/topic/wildlifehabitat/directory.html to find a local rehabilitator or facility that can help.

You can also contact the Wisconsin Chimney Swift Working Group at (608) 658-4139

How Can I Help Chimney Swifts?

Educate friends and neighbors about Chimney Swifts.

    • If you have a masonry or clay flue-tile chimney, keep the top open and the damper closed from April through October to provide a nest site for swifts.
    • Best time to clean your chimney is from November through March before the Chimney Swifts return from South America.
    • If you are converting a furnace or hot water heater to gas, use an alternative venting system, leaving the existing masonry chimney unlined and uncapped for swifts.
    • Swifts also nest in barns or masonry structures such as concrete silos. Keep a top entry open for swifts.
    • Identify and preserve Chimney Swift roosting or nesting chimneys in your community.

Swift on Nest Inside Silo, Photo by Jim Edlhuber
Swift on Nest Inside Silo, Photo by Jim Edlhuber

Chimney Swift Structure Use

There are two types of roosts that Chimney Swifts use: nesting roosts and resting roosts.

Baby Birds
Jack Bartholmai

Nesting Roosts are used during the breeding season. Only one Chimney Swift pair nests per chimney. When nest building they gather twigs in flight, snapping them off with their feet as they pass. An average nest consists of 265 twigs held together with saliva.

Swifts Circling
Dick Nickolai

Resting Roosts are used during migration and also by unmated swifts in summer. Swifts gather in groups (sometimes very large groups) in communal roosts in large chimneys, often whirling in a huge circle as they funnel down for the night.

Babies Waiting for Food
Jack Bartholmai

Chimney Swifts historically nested and roosted in hollow trees. As American pioneers moved westward across the continent, they cleared forests and removed the swifts’ natural habitat. The birds that Audubon called American Swifts became known as Chimney Swifts as they readily adapted to the masonry chimneys erected by those same pioneers. Over the decades, the range of the swifts expanded with the ever increasing availability of this new, man-made habitat. However, environmental changes, including fewer chimneys, are now challenging this species.
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What’s That Sound in My Chimney?

Chimney Swifts create a variety of sounds when nesting. There is the “whooshing” sound of their wings as they come and go from the chimney. They utter a gentle “chippering” as they socialize with one another during nest-building and at night. The most audible sounds are those of the young which includes a very loud, high-pitched “yippering” as they beg for food from the parents, and a mechanical, hissing alarm call made when disturbed or frightened.

Once the sound of the young becomes noticeable, they are usually only 10 days or so from leaving the nest. The homeowners’ tolerance during this critical period of the swifts’ development is very important. Keeping the damper closed and packing the fireplace with insulation can dampen the sound to tolerable levels.

For nesting, Chimney Swifts do not require acres of unspoiled wilderness, expansive wetlands or complicated wildlife management plans. All that is needed is one square foot of unused column such as our chimneys during the summer when not being used…and a little tolerance.

This is an edited excerpt from Rehabilitation and Conservation of Chimney Swifts, Fourth Edition by Paul and Georgean Kyle. Copyright, 2004

Keep Chimney Swifts common in Wisconsin