Chimney Swift Quick Facts
Average body length: 5 inches
Average wingspan: 12 inches
Size and Shape: Adults measure about 5 inches long and have a 12 inch wingspan. In flight, their wings are shaped like a narrow half-crescent. They have a very short neck, a cylindrical body, and no descernible tail, leading to the nickname of ‘flying cigars.’
Perching Habits: They don’t perch on branches or other horizontal surfaces, but have instead adapted to cling to the side of rough vertical surfaces (such as brick) with their long sharp claws. Ten stiff spines on the tips of their tail feathers help support them.
History: Chimney swifts were originally named in 1758 by Carl Linnaeus, who thought they were swallows. They were later renamed American Swallows or Chimney Swallows. Their closest relatives include Vaux’s Swifts.
Range: Their range is the eastern half of the US and southern Canada. A very similar species, Vaux’s Swifts, live in the Pacific Northwest and in southwestern Canada.
Life Expectancy: Their life expectancy is 4.6 years, but the oldest swift on record was at least 14 years old when it was captured and released by an Ohio bird bander in 1970.
Feeding: Swifts are “aerial insectivores,” which means they feed exclusively on the wing, spending their days flying overhead and scooping up and eating insects. Swifts even drink and bathe on the wing. They glide down to the water, smack the surface with their bodies, and then bounce up and shake the water from their feathers as they fly away.
Nesting: Swifts nest one pair to a chimney and sometimes have a ‘helper’ bird, which may be last year’s baby, to help feed their young. The babies are fed ‘spitballs’ of insects that are gathered by the parents. The tranfer of the parents’ saliva to the young is thought to help strengthen the babies’ immune systems.
In the summer, unmated swifts continue roosting together in chimneys, sometimes in large groups.
Their nests consists of tiny twigs that the birds snap off in mid-flight using their feet. In May and June, swifts can be seen fluttering above trees that have some dead twigs on top, looking for suitable nest material. The twigs are transferred from their feet to their beak and then ‘glued’ together using their own saliva to form a half-cup nest on the inside of a chimney or other similar location. A completed nest measures 2-3 inches from front to back, 4 inches wide and 1 inch deep. It can consist of over 250 twigs!
Their nests will not cause chimney blockage, damage or fires.
In pre-colonial times, swifts nested and roosted in large hollow trees. Later, as land was cleared for settlements and agriculture, most of these old trees were cut down, and swifts adapted to using chimneys. Modern building construction often does not include chimneys, and many of the older chimneys swifts have used are being capped or demolished, resulting in fewer available nesting and roosting sites.
Legal Protection: Swifts (and all migratory birds) are protected by the federal Migratory Bird Treaty Act of 1918, which protects over 800 species, their parts, feathers, nests and eggs.