This behavior seems obvious when you consider their nesting and roosting behavior – both are done inside chimneys. Historically, these birds nested in hollowed limbs, snags, and even in caves, but have opportunistically adapted to using man-made structures. As homes replaced forested landscapes, the species had no option but to use what was available to them. Chimneys were similar to the hollow trees of which they were accustomed, and this adaptation may have resulted in an increase in their distribution and overall population.
Today, Chimney Swifts are fairly common birds in cities, towns and neighborhoods. However, their population is experiencing a downward trend, due primarily to threats caused by humans. Pesticides are decreasing their available food (beneficial flying insects), and modern furnace technologies are eliminating the need for chimneys, thereby decreasing available nesting opportunities. The first threat is addressed by decreasing the use of broad-spectrum pesticides, and improper use of these chemicals. The second threat is being addressed by the construction of artificial roosting and nesting structures called Chimney Swift Towers.
Since 2013, we have been installing Chimney Swift Towers throughout the region. These unique structures mimic an actual chimney, serving as roosting and nesting habitat for the birds. The central tower is constructed much like a traditional chimney, and the interior walls of the tower provide perfect roosting and nesting opportunities. Most of these structures also feature a kiosk which contains educational information about swifts and swift conservation, as well as wayfinding, site information or community bulletin boards. When properly placed, the towers are inhabited within a year, while others may take a bit more time to contain birds.
Thanks to Allegheny County Parks Foundation, Pittsburgh Foundation and the Allegheny County Parks, we are in the process of installing 100 Chimney Swift Towers in the 9 county parks. The Chimney Swift Towers provide critical nesting and roosting structures for swifts in our area – they act as faux chimneys, which the birds use to raise young and to roost at night. Working with the county throughout the winter and early spring to plan the project enabled us to begin installation of our first tower in May. Since then we have installed 22 towers in North Park and 19 in South Park, and are now turning our attention to Harrison Hills, Boyce Park, and Hartwood Acres. Each of these parks will get 8 towers. Most towers contain a 4-sided kiosk which features educational graphics that depict the importance of Chimney Swifts, and the reason for the towers. The towers have been met with interest and excitement by park users.
Because of their social structure, Chimney Swifts will not allow other birds (including swifts) to use the tower while they are nesting. They defend their nesting structure during the breeding season. So while a Chimney Swift Tower could be used as a roost by one hundred or more birds during migration, a single pair of birds will use the structure during the nesting season. Therefore, each and every tower we are able to build is critical in supporting the Chimney Swift population, and ensuring they remain relatively common birds in western Pennsylvania. Look for our Chimney Swift towers in municipal parks, county parks and school grounds near your home.