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Chimney Swift

Chimney Swift
Chimney Swift

© Greg Lavaty

Chaetura pelagica

Family: (Apodidae) Swifts

The Chimney Swift is a member of the swift family which also includes the Black Swift and the White-throated Swift (the common swift west of the Rockies). Chimney Swifts range throughout eastern North America from North Dakota to Maine and south to the Gulf Coast. They winter in Peru. Their closest relative is the hummingbird.

The Chimney Swift is a small bird, rough 5" long and dark-gray in color. As with all swifts, it has a short bristle-tipped tail and slender, curved-back wings. In flight the swift calls with a twittering of rapid, repeated chips. The Chimney Swift can be distinguished from swallows and martins by its lack of forked tail and its narrow, long wings on a relatively small body. The swift is often described as a "flying cigar".

Chimney Swifts begin to arrive in Houston in March. A few still nest in large hollow trees; however, most nest in chimneys. Typically there is one nest per chimney. Roosting swifts often use the same chimney, usually perching in the upper portions, so determining just how many nests are in a chimney is difficult. Both sexes help in nest-building. They hover by trees and break off twigs which are then fastened together with saliva to form a semicircular basket and attached to the chimney wall. By mid-June 3 to 6 pure white eggs are laid. Incubation takes 18 days and then the young usually stay in the nest for 24 days. At first they exercise their wings while staying in the chimney by bracing their tails against the walls and flapping their wings. Both the father and mother help with incubating and raising the young. Sometimes other adult swifts will also help with feeding duties. The young are ready to leave the nest usually in late July to early August. Swifts flock together after the nesting period. In late summer they congregate in large staging groups as they prepare for migration. They begin to leave in the fall with most gone by late October.

Invite Chimney Swifts to Your Yard

Chimney Swift nest
Chimney Swift nest

Courtesy of Don Verser

Chimney Swifts are highly beneficial birds from man's point of view. They are voracious eaters of flying insects including mosquitoes, flies, ants and termites. Unlike martins, they don't mind if a yard has tall trees. Their only requirement to nest is a chimney (non-ceramic, non-metallic) or chimney-like structure. If you have a metal or ceramic chimney, please cap it to prevent swift injuries. If you would like to have Chimney Swifts nest in your chimney, remove any grate that may be on the top during the nesting season (March - October). The only precaution you must take is to make sure the chimney flue stays closed. When there are young in the chimney, you may hear some fluttering from time to time which sounds very close to the flue. This is caused by the young exercising their wings and is no reason to panic. Swifts leave very little debris in the chimney from their nesting activities and are very clean birds.

If you decide you do not want swifts to use your chimney you should close off the chimney entrance with a wire grate. This procedure should be done in the November - February period, when there are no swifts in our area. It is against the law to tamper with the swifts and their nests once they have started using your chimney.

Chimney Swift Towers

Sometimes it is impossible for swifts to use your chimney, either because of its design or because of problems with predators. In the past few years several designs have been developed for chimney swift towers. Plans for towers and more information about Chimney Swifts may be obtained from the links below.

Conservation Status of Roosting Chimney Swifts

by Georgean and Paul Kyle of the Driftwood Wildlife Association

Posted on Texbirds on May 16, 2007.

While a large number of roosting swifts does not mean a large number of nests (one nest per structure is the norm regardless of the size of the structure), it does not preclude the existence of an actively nesting pair of swifts, and disrupting even one pair is a violation of the Migratory Bird Treaty Act. In fact, it is not uncommon for a nesting pair to share a structure with a roosting flock. The nest is generally low in the structure while the non-breeding birds roost over-night in the upper portion. We have observed this behavior for more than 20 years in the towers that we have built and maintain at Travis Audubon's Chaetura Canyon Bird Sanctuary and Chimney Swift Observatory. There are currently two towers on the property with this configuration at this time.

Large structures such as the Pershing Middle School stack are being decommissioned on a regular basis all across North America. They are not only important migratory way stations for the swifts, but places where increasingly large numbers of non-breeding swifts can find relative safety throughout their stay in the northern hemisphere.

As recently as two decades ago, Chimney Swifts were seen roosting in large numbers only during migration -- primarily in the fall. Today it is not unusual to view large numbers of swifts funneling into suitable structures through out the summer months. The speculation is that with the decrease in suitable nesting sites (clearing of traditional habitat with large hollow trees, capped chimneys, demolition and new construction with metal rather than masonry chimneys) non-breeding swifts are congregating in large suitable structures -- like the one at Pershing Middle School.

It should be noted that although Chimney Swifts are often overlooked by birders and conservationists alike, their numbers are in dramatic decline. This is particularly evident on the outer fringes of their breeding range. The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) has recommended that Chimney Swift be listed as "threatened" in that country. This should be a wake up call for those of us in the States.