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Chimney Swifts: Your Questions Answered

The chimney swift is one of four regularly occurring species of swifts found in North America and the most common swift found east of the Rockies. They got their name because they have become accustomed to building their nests in chimneys, as well as abandoned buildings and occasionally stone wells.

Because they are so often associated with chimneys, these are critters we come across fairly often – and we get quite a few questions from customers too. Let’s address some of the most common.

Chimney Swift penciled drawing - they are a protected species

Q: How Rare Are Chimney Swifts?

According to ornithology experts, these fascinating birds have been in a population decline for some time now. Between the years 1966 and 2019, the species has been reduced by about 2% every year – meaning in total, the population has decreased by 67% in the last several decades. 

Some sources hypothesize that if the decline continues, the worldwide population of chimney swifts will be cut in half in just 27 years.

Still though, some scientists estimate the global breeding population sits around 8.8 million, making them relatively common in cities and towns across North America.

Q: Are Chimney Swifts Protected Birds?

Yes – this species of bird is federally protected. Once known to nest in caves and hollow trees in rural areas, chimney swifts now often build their nests in human-made vertical structures like chimneys and other vents (a result of widespread deforestation). 

Because of this, they are protected under the Migratory Bird Treaty Act of 1918. This means that if you find one in your chimney, it cannot be removed. Removing the birds or their young can result in fines and put you in some trouble.

So…what can be done, then? All that’s left to do is wait until they fly south again. Once they’re out, you’re okay to have their nesting materials removed, so you can use your chimney safely once again. We’d also recommend ensuring your chimney is secured with a well-fitted chimney cap. That way, come next spring, they won’t be able to return and cause any issues or delays.

Q: How Can I Help Conserve Chimney Swift Populations?

The biggest thing you can do – which is often a bit of a nuisance or irritant for you – is to leave them be, should you find a nested family in your chimney.

In addition, educate yourself and your neighbors about them, their behavior, and their habits. Look for local organizations that protect birds such as chimney swifts and get in touch to see what else you might do to help – such as learn how to build a chimney-like alternative for them to roost in!

Questions? Comments? Concerns? We’re here to help in any way we can. Contact us right here through our website, or give us a call at 615-459-2546 to learn more.

Q: What Do Chimney Swifts Look Like?

Adult chimney swifts are most commonly seen in flight and usually in groups. When soaring, their long, scythe-shaped wings span about 12 ½ inches, supporting a proportionately short body with a squared-off tail. You will notice a flickering, bat-like flight when flapping that is due to short and massive wing bones. 

Watching swifts is truly magnificent, as they create spectacular aerial ballets. These acrobatic moves are most often created as they patrol the skies for mosquitoes and the other small flying insects that constitute the majority of their diet. You will hear a sharp chipping or ticking call that accompanies the swifts as they fly.

At rest, an average 5-inch, 8-ounce adult is sooty gray to black with the throat slightly lighter, or even silvery gray, in color. The sexes are identical in appearance. Both the claws and tail bristles are used to cling to rough vertical surfaces – this is one reason they like to nest in chimneys. Swifts are actually unable to perch or stand upright in passerine fashion.

Q: Where Do Chimney Swifts Originate From?

While they are native to regions throughout North America, chimney swifts spend their winters in South American areas like the Amazon Basin of Peru. They arrive in the continental United States in late March and are typically gone by early November.

Q: What Are Their Nesting Habits?

Nesting begins in May and can continue into August. Chimney swifts are usually single-brooded, which means they lay eggs once a season. The female normally lays three to five white eggs in a nest of twigs broken from the tips of tree branches, glued together with saliva and attached to the inside wall of a chimney.

Both sexes are involved in nest construction and alternate incubating the eggs for 18 to 19 days, when the young begin to hatch. Their parents catch flying insects on the wing to feed them until the birds fledge from the chimney about 30 days after hatching. The hatchlings are pink, altricial and completely naked at birth. They have sharp claws, which enable them to cling to textured surfaces and, within a few days, black pin feathers begin to appear. The young are able to climb, and they exhibit preening behavior even before their feathers emerge.

Q: When Do Baby Chimney Swifts Leave the Nest?

  • By the time they are 8 or 10 days old, the babies’ feathers begin to unfurl.
  • By 15 to 17 days of age, their eyes begin to open. Soon, most of the flight and body feathers will be unfurled, but the feathers around the face and head will stay in sheath for several days, giving the birds a frosty-faced appearance.
  • By the time chimney swifts are 21 days old, they will cling tightly to the nest or chimney wall, rear back, and flap their wings furiously until they are panting and out of breath.
  • At 28 to 30 days after hatching, young swifts will leave the safety of their chimney nests for their first flight.
  • Once an entire brood has fledged, they will fly with their parents in slow, noisy parades around the area of the nest site in search of food.

The young will return frequently to the roost during the first few days, but will soon begin to visit other roosts in the area. At the end of the breeding season, the swifts’ communal instincts peak prior to fall migration. They congregate in flocks of hundreds and even thousands at suitable roost sites. Although chimney swifts can withstand a few early cool snaps, they will usually ride south on the first major cloud front that blows through in the fall.

Q: How Can I Avoid Chimney Swifts Entering My Chimney?

One easy thing you can do is ensure that you schedule your annual chimney sweep service in early March before the birds return from their South American migration. During this service, you may also choose to have a new chimney cap installed to prohibit any nesting activity.

Any Other Questions?

Any other questions about chimney swifts or your chimney? We’re here to help. Call us at 615-459-2546 or reach out online today.


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