The Chimney Swift is bird which nests, roosts, and feeds mainly in urban areas, such as the City of Ann Arbor. They look like cigars with wings, and are charcoal gray, with stiff wingbeats, and a notable chittering call. They eat up to 1/3 of their body weight in insects each day, and thus benefit us greatly. These birds used to nest in old growth hollow trees. When these trees were lost to logging, the birds adapted to using chimneys to nest and roost. Now chimneys are essential to their survival. Chimney Swifts cannot perch on tree limbs like birds, because their special foot shape can only cling to a vertical surface.
The chimney at 415 W. Washington is a good example of a large Chimney Swift roost, hosting at least 1,400 swifts in August 2018.
These birds roost in great numbers, huddled together for warmth in chimneys at night, during spring and fall migration, and throughout the breeding season. A single pair will use one chimney for nesting, but other non-breeding birds need chimneys for roosting too. The loss of large chimneys for roosting is one reason that this species is in steep decline. This species has lost more than 70% of its population in the last 50 years. Capped or metal chimneys cannot be accessed by these birds. Older buildings with chimneys are being torn down and replaced by buildings which may not have chimneys.
The sight of Chimney Swifts spiraling into chimneys at dusk is enjoyed by many in Ann Arbor. Watch hundreds of swifts enter the chimney at 415 W. Washington in the video below.
General Chimney Swift Information
Washtenaw Audubon Society - Chimney Swift Fact Sheet
Michigan Audubon Society - Chimney Swift Conservation
All About Birds - Chimney Swift
Wisconsin Chimney Swift Working Group
Ontario Swift Watch
415 W. Washington Building
Resolution to Direct the City Administrator to Evaluate Preservation of the Chimney Swift Roost at 415 West Washington Street
Historical pesticide applications coincided with an altered diet of aerially foraging insectivorous chimney swifts