|Cool fact: Chimney Swifts perform an aerial courtship display by holding their wings stiffly upward in a V, one bird gliding closely after another, their chirping calls run together as a twittering song. Occasionally a third or fourth swift joins in pursuit.|
As a group, swifts are highly specialized for high-speed aerial life. They have long, saberlike wings that are either extended in flight or folded back when at rest; unlike swallows, they are never held bent at the joints. Compared to swallows, swifts are less maneuverable and are less adept in flight at low speeds. Swifts forage for flying insects, sometimes quite high in the sky, and drink by dipping their bills in water while flying. Some species are even thought to sleep while flying in "aerial roosts," and it is also believed that Chimney Swifts can copulate in flight.
Chimney Swifts are widespread and common throughout North America east of the Rocky Mountains. On occasion, some have bred in Southern California and possibly in Arizona. Large flocks gather in the fall and roost in chimneys, sometimes by the hundreds or even thousands. The majority departs the breeding grounds in late August or September to begin the long migration south. Flying by day, they cross the Gulf of Mexico and travel through Central America to winter along river edges and the edges of tropical lowland forest in Amazonian Peru.
As forests with large hollow trees have disappeared, Chimney Swifts have readily taken to nesting in chimneys, and populations probably increased with the proliferation of suitable nesting sites. In recent decades, however, populations have declined at a rate of almost six percent per year. Chimneys provide upright surfaces sheltered from the weather much like hollow trees, and other sites that have been used for nesting include wells, silos, and the insides of abandoned or seldom-used buildings. The nest is a half-saucer composed of dead twigs plucked in flight with the feet, glued together and adhered to the chimney side with the swifts' hardened saliva. Chimney Swifts use their long, sharp claws to cling to the sides of chimneys.
Description: Chimney Swifts have been described as a "cigar with wings." They have streamlined bodies with stubby, blunt tails and short, wide bills. They are uniform gray-brown above; the underparts are dark brown from midbreast to the tail, and the throat is light gray gradually darkening toward the breast. The long, slender wings are black-brown, with slightly lighter flight feathers. The tail is dark gray-brown, but little of it shows except when it is spread. Each tail feather ends in a spine that extends past the web.
The similar Vaux's Swift (C. vauxi) breeds from California north to British Columbia. It is slightly smaller than the Chimney Swift and has a larger and whiter throat patch that extends into the midbreast. The colors of the lower breast and vent area are lighter than the colors on the Chimney Swift. The upperparts of a Vaux's Swift show a contrast between the dark mantle and lighter rump, unlike the more uniform dark upperparts of the Chimney Swift.