Chimney swift (Chaetura pelagica )
Dynamics of Asheville chimney swift roost system during 2020 autumn migration
de·scrip·tion
Chimney swifts (Chaetura pelagica ) are small birds that have adapted to live within man-made structures. They have long, curved wings and small bodies, making it impossible for them to perch. They instead cling to vertical walls, either inside of a tree or cave, or more commonly, a chimney.
ad·ap·ta·tion
When European colonists first moved to America, swift habitats were destroyed through deforestation. The birds then adapted to living inside the colonists' chimneys, using the bricks to build nests with twigs and their saliva. Since then, chimney swifts have been members of many urban ecosystems across the eastern half of the US.
Chimney swifts migrate from South America to the US as early as April each year. From then until mid-October, they will breed, raise young and join other groups of swifts before heading South again for the winter.
Swifts will use one of three main routes to migrate between North and South America; the Mississippi River, the Appalachian mountains, or along the Atlantic coast. Asheville, NC sits along two of these migratory paths (The Appalachian and the Mississippi River flyways), making it a key location for roosting.
dem·ol·ish
More masonry chimneys are being destroyed than built in recent years, meaning swifts are once again facing habitat loss despite previously adapting to human interference. Chimney swifts are considered vulnerable to extinction by the IUCN Red List of Threatened Species. Understanding swift roosting patterns is important for habitat conservation efforts, but little long-term research exists on these issues.
sur·vey
A season-long survey was published in 2021 to understand roost-site range and selection patterns by chimney swifts within Asheville. While annual roost locations are usually well-documented within local birding communities, few studies have consistently recorded the condition and use of roost sites during an entire breeding season.
hy·poth·e·sis
Researchers tested two hypotheses regarding how chimney swifts select roost sites throughout their time in Asheville: either they choose one roost site and stay there until they return South (concurrent roost-use), or they move to different sites as the breeding season progresses (sequential roost-use).
find·ings
The study found that most roost sites were not occupied by swifts through the entire season, the only exception being the Merrimon Avenue site. Early in the season, most sites had small populations that likely consisted of local swifts and early migraters. As the season progressed, however, these birds would join up with other groups and move into other vacant chimneys, supporting the sequential roost-use hypothesis.
con·ser·va·tion
Swifts have become important parts of urban ecosystems, especially in keeping mosquitoes and other bugs at bay. It is in our best interest to help them increase their numbers, and there are many ways to help swifts thrive.
what you can do
Learn to identify chimney swifts and keep an eye out for them at dusk in the summertime. If you have an older chimney, you can make it "swift-friendly" to help facilitate habitat growth in your area. If your chimney is lined with metal, cap it during the warm months to prevent swifts from becoming trapped inside.
get·involved
in your community
Blue Ridge Audubon is Asheville's local Audubon Society chapter. They host a variety of bird-watching events and meetings, which are open to all members of the public.
You can find bird data and information specific to North Carolina at Birds of North Carolina.
nationwide
If you see chimney swifts going into a roost site in your area, go to A Swift Night Out to report the location and estimated number of swifts. This is a nationwide database used by birders and wildlife scientists across the country. They also have many local chapters that host swift-watching events each year.
