Cool Facts

• Before European settlement of North America, the Chimney Swift probably nested in caves and hollow trees. The swift benefited greatly by the construction of chimneys and the increased availability of new nest sites. Recent changes in chimney design, with covered, narrow flues, have decreased the available nest sites and may be a factor in declining population numbers. For information about a Chimney Swift tower made specifically for nesting swifts, go to the North American Chimney Swift Nest Site Research Project.
• Chimney Swifts do not sit on perches like most birds, but instead use their long claws to cling to the walls of chimneys and other vertical surfaces.
• Swifts are among the most aerial of birds, flying almost constantly except when at the nest or roosting at night. The Chimney Swift bathes in flight, gliding down to water, smacking the surface with its breast, then bouncing up and shaking the water from its plumage as it flies away.
• The Chimney Swift is gregarious, with large numbers of swifts roosting together in a single chimney or air shaft during the nonbreeding season. Nonbreeding swifts will roost together in the summer too, and this behavior has fooled people into thinking that the Chimney Swift nests in colonies. In fact, only one pair nests in a single chimney. The pair may tolerate other swifts roosting in their chimney, though, further confusing people watching the swifts from the ground.
• The fast, erratic flight of the Chimney Swift is characteristic of small swifts. It gives the very distinct impression that the swift is beating only one wing at a time, alternating wings. Careful investigation has shown, though, that a swift beats both its wings at the same time just like all other birds. The illusion comes at least in part from the frequent banking and turning.