A Peek into the Life of a Chimney Swift

Mark Armstrong, master bander of both songbirds and hummingbirds, and his wife Janie Kading, have a chimney swift tower that Mark constructed in their back yard   

For several years swifts have nested in the tower.  Small holes are drilled in the bottom of the base so that you can look up and actually see how many nestlings have their heads over the nest edge and how many swifts are roosting on the chimney wall.

This breeding season a pair of chimney swifts raised at least three young in the tower. The nests are shallow and when considering its small size, it is hard to imagine how three nestlings can fit into it.  Both the male and female bring sticks to build the nest, breaking them off with their feet and carrying them to the nest site in their beak.  The twigs are then sealed with sticky saliva from the swift's seasonally enlarged sublingual glands

Even more fascinating is the description found in the account of Birds of North America notating the timing of egg-laying.  "Egg-laying begins when nest half-finished at about 3-6 d, and new twigs and saliva added during incubation...."  The pair stops adding sticks shortly before the eggs hatch.

On July 1st, Mark and Jane set up traps to capture and band hummingbirds in their yard.  In addition, to the hummingbird traps, a mist net was set up to capture hummingbirds and possibly a swift as it left the tower after feeding young.    

Above, you see the band being attached to a swift's leg.  A swift's feet and legs are weak, similar in structure to those of the hummingbird, and are used for gripping and grasping but not for perching.  The chimney swift is airborne most of its life and uses its sharp claws to cling to vertical surfaces while roosting.  Also, notice how long the wings are in relation to the body.

The swift's interesting tail structure also is clearly an additional support while roosting. The feathers end in sharp barbs that help to support the bird while clinging to the roosting surface.  

Below you see two adult swifts resting after feeding young in the nest.  Though the image is not exceptionally clear, you can see that the birds are not just clinging with their feet but are using their tail as support while resting.

After the young fledged, other swifts in the area joined the family in the tower at roosting time and as many as 15 were counted before all the swifts departed on migration.  Presently, swifts are migrating through our area and known communal roosts are being monitored to count the number of swifts as they enter the chimney. The highest count from one chimney that I've seen reported to date was 10,000 in the Nashville area (reported last week).

Links and Resources:

Chimney Swifts coming to roost during migration
Chimney Swifts
Mark Armstrong also banding hummingbirds
Swift Night Out
Chimney Swift Tower
Knoxville Chapter, Tennessee Ornithological Society
Tennessee Ornithological Society

Swift Night Out--Lenoir City, Tennessee

Swift Night Out is a fun and amazing way to spend an evening.  Not only are participants helping to count chimney swifts during migration but they personally experience one of nature's avian wonders--the high-speed roosting ritual of chimney swifts.

The show begins at dusk and lasts about 30 minutes. When we first arrived at the site, the historic War Memorial Building in Lenoir City, Tennessee, it was about 8:10 pm. We saw and heard one swift overhead but in less than five minutes, hundreds appeared flying overhead, some coming down near the tops of our heads and curving past us. Suddenly, they seemed to be everywhere. Swifts initially swirled around the chimney in fly-bys, until eventually, one by one, they began dropping into the chimney. And that's what it looks like, as though they've turned off the "engine", and with heads pointed downward, allow gravity to propell them into the chimney.

The mass momentum builds until dozens of birds may descend in rapid succession.  At one point, the sky suddenly became silent.  No sound.  No birds.  Denise described it as happening routinely, "as though someone turned off a faucet" and I agreed.  Another burst of activity followed beginning a few minutes after the pause, and lasting only a few minutes more until the flock was settled in for the night.


My videos will introduce you to the phenomenon but it is definitely one of those events that you will want to experience in person.  In the video background you can hear a generator but the chirping of the swifts overhead can still be clearly heard.  Just how swifts synchronize this roosting frenzy so that everyone lands safely inside is beyond comprehension.  One wonders how they know about the chimney and judge its walls to be safe.  How can over 500 swifts find roosting space in a chimney that does not appear all that large? How do the birds manage to grab a perch while in the midst of communal high-speed descent?  Are these birds local birds gathering prior to migration or migrants passing through or both?



Denise and Tony King, of Lenoir City, members of the Knoxville Chapter of the Tennessee Ornithological Society, have been watching and counting chimney swifts in Lenoir City for about six years. They first became interested when they noticed the large numbers of swifts coming to roost in a chimney in their neighborhood.  That roost site is no longer there but it spawned their interest and a search around town revealed other migration roosting sites.  The historic War Memorial Building chimney is the largest and most active they've found in the area.  

Above, a chimney swift held in a banders grip.

Denise and Tony participate in a Swift Night Out, an effort to increase interest in swifts and to locate and count migrating Chimney Swifts and Vaux Swifts.  Chimney swifts are believed to be declining due to the destruction of old chimneys commonly used for roosting sites and required for nesting.  Old chimneys found at industrial sites, churches and older homes are likely places for a communal roost.

To find a known swift roosting site near you visit the website's list of 2012 roost sites all across the country and click this link to see reports thus far in 2013 . A phone call to your local birding organization may also help you get acquainted with members who can introduce you to a roost site.

Next:  A look at Chimney Swifts from the banding table

Links and Resources:

Chimney Swifts at Cornell All About Birds
Swift Night Out
Chimney Swifts.org
War Memorial Bldg--Lenoir City
Knoxville Chapter, Tennessee Ornithological Society