North American chimneys east of the Rockies are often occupied by roosting flocks of Chimney Swifts. These birds are also tireless fliers-masters of the air.
Bird or bat?
The sun is setting in a clear summer sky when your eye is drawn skyward by an odd twittering sound. Even stranger, you observe a gathering of some flying creatures wheeling above an old brick chimney. Around and around they circle, with a few individuals dipping suddenly toward the chimney top then returning to the rest. Their darting dipping movement and the twittering sound reminds you of bats, but something is wrong: bats emerge at dusk and fly away—these flyers seem to be congregating. Then, one or two drop abruptly into the chimney, and soon the whole wheeling darting flock spirals suddenly into the chimney like a small tornado being sucked down a manhole; like something out of Harry Potter. Now the air is empty and silent. What have you seen? They’re not bats, and they’re not chimney sweep birds, they’re Chimney Swifts, Chaetura pelagica.
Chimney Swifts
The Chimney Swift, sometimes called the American Swift (the similarity of chimney swift to chimney sweep no doubt accounts for another common name—chimney sweep birds), spends its days on the wing hunting insects, and nights clinging to vertical inner walls of hollow trees, chimneys, abandoned buildings and old stone wells. Before Europeans colonized North America and removed many of the old hollow trees, Chimney Swifts roosted almost exclusively in trees. They adapted readily to chimneys, however, and actually increased in numbers.
Chimney Swifts are migratory birds, spending their winters in Peru and the Amazon Basin. They appear in North America in early spring, and nest in May, with each pair raising three to five chicks. Young birds fledge by about the thirtieth day and join their parents in flight. In the fall, young and old congregate in large numbers and as soon as the weather turns cold and flying insects start to decrease, they are gone.
Interesting facts about Chimney Swifts
Chaetura pelagica is a fascinating bird. Here are some interesting facts about Chimney Swifts:
A Chimney Swift can eat a third of its weight in insects every day. Many annoying and biting insect pests are removed from our environment by these voracious birds.
Chimney Swifts do not perch or walk on the ground: their feet are designed for clinging to vertical surfaces. From the time they exit the chimney to the time they reenter it, they never land.
The tail feathers of Chimney Swifts are tipped with stiff bristles, which help them stay in place while clinging to a vertical surface.
Chimney Swifts have to do everything while in flight—catch flying insects, grab airborne nesting materials, and break twigs off trees for nest building.
The nest is built mostly of twigs, glued to each other and to a vertical wall with saliva. While building, the bird’s salivary gland greatly enlarges to meet the demand.
There is usually only one active nest in any one chimney or tree—thus, the funnel of birds you see entering the chimney are roosting, not nesting there.
Some flocks of migrating birds contain both swifts and swallows.
The Chimney Swift is apparently declining once again, partly due to the disappearance of many old chimneys. To help conserve Chaetura pelagica, some people are preserving old brick chimneys, saving them from demolition, or building chimney-like structures where Chimney Swifts can roost and nest.
Firefly Encyclopedia of Birds. Perrins, Christopher ed. Buffalo: Firefly Books, 2003
The copyright of the article Facts About Chimney Swifts in Birds is owned by Rosemary Drisdelle. Permission to republish Facts About Chimney Swifts in print or online must be granted by the author in writing.
I had the most wonderful experience this week! I saw the sky was black and
moving as if it was alive. I followed the twittering tornado shaped funnel
to find thousands of Chimney Swifts descending upon the large chimney of
the old abandoned high school in our neighborhood. I was mesmorized for 30
minutes as they took turns diving into the chimney attached to the old
cafeteria. I was so moved by the experience, I took my son there tonight to
show him and they never came...I was so sad! I realize now, the chill in
the autumn air must have sent them further south. We are in Central
Mississippi, so I probably won't see them again until next year. It was
something I will never forget! Jane Wasser Carthage, Mississippi
May 23, 2009 2:35 PM
Guest
:
I believe I have a swift in my chimney, but it is colored more like a Vaux
swift, being lighter grey-brown with a brown crown. It does not look like
a swallow. Its nest is in my chimney with 5 white eggs. Nest size and egg
count is typical for a swift. Any ideas?
May 25, 2009 4:34 AM
Rosemary Drisdelle
:
Four species of swift are found in North America: the Chimney Swift, the
Vaux's Swift, the White-throated Swift, and the Black Swift. The Chimney
Swift is found in the east and doesn't overlap significantly with the other
three, though birds do wander outside their normal ranges sometimes! Thus,
location is an important factor in any attempt at identification. The
Chimney Swift and Vaux's, both overall gray or brownish gray with a pale
throat, are quite difficult to tell apart. These two regularly nest in
chimneys.
Jul 7, 2009 3:55 AM
Guest
:
My living room is so loud with birds you can't hear a thing but chirping.
I hate to run them off but the fluttering and the noise. How long will
this last. I like that they eat the insects. I don't know if it's swifts or
sweeps. I guess the netting is off of the top of my chimney.
Jul 7, 2009 6:04 AM
Rosemary Drisdelle
:
If you decide to put netting over your chimney to exclude birds, I hope
you'll have a careful look first to ensure you're not trapping adults or
young inside. Putting up with the noise for a week or two until young birds
fledge seems a small price to pay for a clear conscience.
Jul 9, 2009 9:14 PM
Guest
:
I had an inspector come to check out our chimney after hearing chirping
inside. He confirmed chimney sweep birds. I wouldn't mind letting them stay
until the young are able to fly but how long does that take? Does the whole
family leave or do they continue to nest inside the chimney? Also, do we
have any concerns as far as inside the home (ie fleas, mites, them flying
inside, etc.)? Thank You, Tamika Cleveland, OH
Jul 10, 2009 5:08 AM
Rosemary Drisdelle
:
Please don't try to evict nesting Chimney Swifts from your chimney
(actually, in the US, they're protected birds and it's illegal to remove
active nests). I highly recommend this site www.chimneyswifts.org for
detailed information about Chimney Swifts. Follow the link titled "Is
There Chattering in Your Chimney?" and then "Being a Good Chimney
Swift Landlord" for answers to most of your questions. I don't think
there are significant issues with anything coming into the house if you
keep the damper closed and/or install a piece of styrofoam as the other
site suggests. I would be delighted to have this problem - but as I don't
have a brick chimney, I guess I never will. I hope you can enjoy your
swifts.
Jul 27, 2009 7:17 PM
Guest
:
We've had swifts in and out of our chimney since 1995. We knew they were
birds..got used to the noise..turned up the T.V...watch our cat go nuts
looking at the sound. When they left.. we missed them. They get here about
late March and stay until about late October. I guess they like us..they
come back every year.We like the idea of our own insect patrol. The
Stanley's.. South Mississippi
Aug 5, 2009 6:58 PM
Guest
:
My wife and I own a condo in an old midwestern brick and mortar school
building, which has been converted into 12 apartments. The building has an
old smokestack, typical for a building built in the 1920's. The stack has
not been in use for at least 20 years.
It is wonderful to
watch the swifts dart in and out of the stack at dusk, but we and others
who live in the old school have worries about what affect the swifts may
have on the building: 1)Do the feces that fall to the bottom of the stack
in the basement pose a potential health problem to us? 2)Does the
accumilation of nests pose a potential problem with causing the motar to
decay more quickly?
We don't really want to cause harm to the
swifts, but neither do we want to expose ourselves to unintended
consequences.
Any advice?
B. Thompson Indiana
Aug 6, 2009 5:09 AM
Rosemary Drisdelle
:
No authoritative answer to either question above - I'll leave it to the
specialists. Having said that, issues with disease spreading through bird
droppings generally arise when an accumulation of droppings is disturbed,
so unless someone is accessing the base of the chimney and stirring things
up, I wouldn't worry. As for the chimney, I would think that any brick
chimney that has been out of use for twenty years should be checked for
structural safety in any case (but not while the birds are nesting!).
Aug 16, 2009 6:44 PM
Guest
:
I am wondering if anyone has been attacked by these birds before? I have a
family living in my fireplace, which is great! Tonight I was standing on
my deck, just before dark, taking photos of my hummingbirds, and the nice
family of Chimney Swifts came right at me and I swear one touched me.
Nothing like this has ever happened to me before? Is that
"normal" for these birds?
Jul 5, 2007
