Bird of the Month: Chimney Swift
Chimney Swift. Photo by Ryan Mandelbaum, CC BY 2.0.
By Roger Digges, CCAS Vice-President
You won’t see June’s bird of the month at your feeders, nor perched in your yard, or perched anywhere for that matter. This bird belongs a family that people thought for many centuries had no feet, because no one ever saw them perch, hence their family name, Apodidae, from the Greek apous, which means without feet. These “footless” birds nested in caves, hollow trees, and on cliff faces until Europeans brought chimneys to North America. Although some still cling with their long claws (yes, they do have feet, just not feet suitable for perching) to the sides of caves, hollow trees, and cliff faces to perch or affix their nests, most of the species adapted to the new structures these human beings built. Newcomers from England called them Chimney Swifts, to distinguish them from the swifts they knew in the old country (which also used chimneys, but were simply known as swifts, being the fastest bird in level flight they knew).
After overwintering in northwestern South America, Chimney Swifts arrive in our area in mid-April and remain until mid-October. Because these birds fly constantly through the day, even to take a bath, dipping into the water, the best way to find them is to look into the sky, almost anywhere in our area, over woodlands, ponds, residential areas, even over downtowns. While you may also be rewarded with the sight of Turkey Vultures, hawks, falcons, and many other birds, you may see what some birders call “flying cigars,” their short stubby bodies, short tail, and long, curved wings flapping stiffly, marking this bird as a Chimney Swift. Although superficially they resemble swallows in flight, the two are not closely related. Rather they are an example of what biologists call convergent evolution, in which two different species (or in this case, families) evolve the same adaptations to similar needs—efficiently catching flying insects on the wing.
Male and female Chimney Swifts, which look identical, work together to build a nest, breaking off twigs with their feet as they fly through branches, and cementing them with their saliva to the side of a chimney or other vertical surface. Once the female has laid 3 to 5 eggs, she and her mate take turns incubating them for the next 18 to 21 days, and feeding them for the next two to three weeks.
According to AllAboutBirds.org, “After the young fledge, small groups of parents and young from several chimneys join larger staging flocks in bigger chimneys nearby.” It is an incredible experience to watch these flocks at the end of a day, as dozens, hundreds of birds rapidly circle a large chimney horizontally. As the sky darkens, at some unheard signal, individual birds break out of the circle, plummeting into a chimney they will cling to the sides of. It’s amazing that they can do that with such skill.
How are Chimney Swifts doing? Not well. According to the North American Breeding Bird Survey, between 1966 and 2019, their numbers have declined by 67%. While there are still close to 9 million Chimney Swifts in North America, in 1966, there were nearly 27 million. The trend is not good. Partners in Flight cite the destruction of nesting and roosting sites (change in chimney styles, capping of chimneys, residential development in forest sites), human disturbances at nesting and roosting sites, the steep decline in flying insects, and climate change.
How can you help? Put in native plants, shrubs, and trees that attract aerial insects, refrain from using insecticides, preserve or modify your chimney if you can, or if you have space for a chimney-like structure, consider putting one on your property. You can find out how to build one at North American Chimney Swift Nest Site Research Project.