Save Our Swifts: The Role of Chimneys in Swift Habitats

These days, chimneys tend to be a part of a home we don’t think much about. Chimneys are simply decorative, rather than functional and necessary parts of the home. But chimneys are actually a fundamental habitat for another creature that they weren’t originally designed for. Chimneys are a central part of the larger ecosystem for a declining species—the chimney swift, the new official bird of Bethlehem. 

The second panel about the Save Our Swifts Initiative, presented live on March 11th by Bethlehem Area Public Library, offers the Bethlehem community a further look at the unique lives of chimney swifts and the historical evolution of their chimney homes. With panelists like Christine Ussler of Artefact, Inc., Scott Burnet and Peter Saenger of Lehigh Valley Audubon Society, moderator Mary Foltz, Director of the South Side Initiative, and Jennie Gilrain, a key activist behind this initiative, the panel was overflowing with energy and passion for saving the habitats of our local swifts. This panel offered two ways of understanding what it will take to help the Lehigh Valley’s swift population. First, the panel explored the human architectural and social movements that have changed the chimney over time. Second, the panel addressed how the chimney swift has learned to adapt to these changes and make chimneys a home in industrial and post-industrial America.

Slides from Scott Burnet’s presentation on chimney swifts. Pictured above are hundred of swifts circling a chimney they will use for migration.

Christine Ussler presented on the history of the chimney in general, and spoke about many particular chimneys in Bethlehem and their historical significance. The earliest forms of the chimney and fireplace, which were big enough to walk into, were often inefficient. Ussler then described the evolution of the Rumford fireplace —which we would recognize in many colonial-era buildings. The Rumford fireplace more efficiently removed smoke without taking much needed heat from the building, thanks to a constriction at the base of the chimney. Pairs of chimney swifts used these older chimneys as nesting sites.

During the Industrial Revolution, there was a boom in housing and factories, and a subsequent boom in chimneys. Ussler noted some of the earliest residential chimneys that still survive in Bethlehem can be found at the Gemeinhaus, which is now the Moravian Museum of Bethlehem. Notable industrial chimneys in Bethlehem include the one on the site of the old R.K. Laros Silk Mill on E. Broad Street. Industrial chimneys were big enough for thousands of chimney swifts to use them as migration sites. During migration, chimney swifts collect as a group to refuel and rest, before flying to the next chimney farther south. However, current iterations of the chimney have evolved to include chimney caps to prevent snow and rain from getting inside homes, high efficiency furnaces with no chimney at all, and terra cotta and stainless steel flue liners. All of these new evolutions of the chimney are inhospitable for chimney swifts, who need textured vertical surfaces in order to nest and migrate. The bird’s stiff tail and claws make it well adapted to cling vertically to the inside of a brick or otherwise textured chimney. Newer chimney adaptations mentioned above make the chimney swift physically unable to perch on any horizontal surfaces. Likewise, caps prevent the birds from accessing these potential homes, even if the chimney is made of brick or stone. Learning about this historical evolution of the chimney illuminates just how much human trends can impact the ecosystems of the nonhuman species around us. 

This photo from Scott Burnet’s presentation on chimney swifts illustrates how swifts cling to textured vertical surfaces in order to rest, nest, and migrate.

Scott Burnet then went on to present about the chimney swifts themselves, how they live and migrate. Burnet’s presentation built upon the presentation Peter Saenger gave at the first Save Our Swifts panel (read about it here) and described in more detail the chimney swift species. For Burnet, it is important to realize that there is only one type of swift that lives east of the Rockies, and these swifts—our swifts—are in significant decline because of habitat loss and pesticides. This causal relationship is ironic because swifts themselves eat so many insects that they are in fact their own natural pesticide. There is immense potential in supporting chimney swift populations, since we can use less pesticides in our growing practices and potentially diminish their health effects on humans and ecosystems.

With their uniqueness and helpfulness in mind, Burnet outlined the two key conservation methods that the Save Our Swifts Initiative is using to support these birds. One method is building artificial chimneys for swift pairings to nest in. The other is saving existing residential and industrial chimneys that are already being used as nesting and migration sites. The industrial chimneys in particular—like the one saved at the old Masonic Temple site—are important because they house thousands of chimney swifts in a migration season. Groups of swifts follow a pathway of chimneys from the northern United States to South America, using chimneys to rest, refuel, and stay safe from predators and the elements. Incredibly, the chimney swift can fly nonstop across the gulf of Mexico, but in order to do so, they have to rest and refuel in chimneys before they leave on this massive adventure.

In addition to discussing preservation strategies in the Lehigh Valley, Burnet gave information about other innovators in protecting swift habitat. For example, he shared that in the 18th century a woman in Ohio built the very first chimney swift tower, complete with windows and viewing decks to view the chimney swifts. Evidently, supporting habitats of the animals around us has a long tradition. The PA Audubon society has built over 100 chimney swift nesting towers in western PA, and most of these have been readily adopted by swift pairings. Likewise, the unprecedented support of developers like John Noble, who saved the chimney at the old Masonic Temple site which thousands of swifts use for migration, is a key effort in supporting this bird’s declining population. The work of these local activists, organizers, and developers illuminate a model for the kinds of development we might want to adopt on a broad scale—a kind of development that is sustainable, thoughtful, and engages the community to care for every being in our ecosystem. The third panel about the Save Our Swifts Initiative, on Wednesday April 21st, will delve further into this discussion of the possible connections between development and conservation, and feature the perspectives of developer John Noble, Lynn Rothman of the Bethlehem Environmental Advisory council, and Karen Beck Pooley, professor and Director of Environmental Policy at Lehigh University. Don’t miss it!

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