In summer, abandoned brick ventilation towers and factory chimneys across eastern North America become the site of one of the most incredible events in the animal kingdom. Thousands of small black birds, with sleek, dart-like bodies and sharply swept wings, come pouring out of these structures in immense swarms every morning. They disperse over great distances to search for food, then return in the evening to once again enter the man-made structures from which they came. These birds are called chimney swifts.
Before human buildings provided a reliable source of nesting sites, chimney swifts probably nested in caves and hollow trees. Some still do this, but they are few and far between; the majority of them by far now build their nests inside man-made structures. The nests themselves are stuck directly to the wall of the chimney, and are made of a mixture of sticks and the birds’ own spit, which hardens to form a sort of glue. In parts of China, the spit-glue from a related species of swift is harvested to make “bird’s nest soup,” an expensive delicacy.
While our chimney swifts don’t get their nests made into soup, they do have problems of their own. Chimney swifts are categorized as “near-threatened” by the IUCN (International Union for the Conservation of Nature). While they are still relatively numerous, and the huge flocks that they form still exist, they have experienced a drastic drop in population over recent years.
Being hit by cars is one major factor in the decline of the chimney swift. It might seem odd that these fast, high-flying birds are hit by cars, but chimney swifts do not only feed at high altitudes, They also take advantage of the early morning fog and fly close to ground level to catch low-flying insects. It is at this time that most collisions happen, due to the poor visibility and the high speed at which they are traveling. In fact, a study conducted in 2008 found a total of 36 dead chimney swifts on a highway in Indiana.
Another reason for this decline is the lack of available nesting sites. As mentioned earlier, chimney swifts rely almost entirely on abandoned chimneys and ventilation towers as places to build their nests. However, most old buildings are not kept up long enough for swifts to use them. They are demolished, or they are repurposed into new buildings and their chimneys and ventilation systems are refitted. Either way, this denies chimney swifts a place to nest. In Davidson we are fortunate enough to have a chimney that is used by chimney swifts. It is on the grounds of the Lake Norman Christian School (formerly the Davidson IB School), and serves as a nesting and roosting site for hundreds of swifts.
Chimney swifts are also at risk from pesticides. Like many birds, chimney swifts feed on insects, and the use of pesticides to kill insects deemed harmful to crops and gardens may have the unintentional side effect of depleting entire insect populations. While also encouraging gardeners and farmers to find no ways to increase their yields, there must be more research performed into alternatives for pesticides.
What can be done in the meantime? While the threats posed by cars and pesticides may be too broad to change within the context of one town alone, there are things that can be done regarding the swift’s nesting sites. Rather than being demolished, old buildings with tall chimneys should be preserved as nesting areas for chimney swifts. Moreover, private citizens and companies should be encouraged to build artificial “swift towers” atop their houses and work buildings. These chimney-like structures are designed solely for the use of chimney swifts, and are provide them with additional nesting sites if their original ones are destroyed.
Another possibility is the idea of holding “swift-watching” tours—guided, scheduled outings in the early morning or late evening of every summer with the purpose of showing townspeople the spectacle of the chimney swifts emerging from and returning to their chimneys. Holding these tours would allow people to learn more about swifts, and possibly begin to care enough to preserve them.