The Swift is universally known as the Chimney Swallow, from a belief that it belongs to the swallow family. It is, in fact, no relative of the swallows, but very nearly related to the Whippoorwill and Night-hawk. Swifts and swallows both have long, powerful wings, which enable them to remain for long periods on the wing in a restless search for insects. Scientists themselves were for a long time misled by the resemblance in the appearance and habits of the two families, but a close examination of the skeleton of the two birds has convinced naturalists that the two families descended from different ancestors, but have arrived at similar solutions of the problem presented to them in their search for food.

The Swift builds, as is well known, in the flues of chimneys. It is often seen in May, dashing past the dead twigs of some tree, and then off to the chimney, where the twigs are glued together and to the bricks by the help of saliva secreted by the bird. A common and distressing experience after a storm in summer is the discovery of the young Chimney Swifts at the wrong end of the chimney,—on the hearth, in other words. Even in their proper place in the chimney, the young birds can make their presence very well known by beginning, as soon as it is light, an incessant clamor for food.

The long narrow wings, the powerful chest muscles, the cut of the bird's body, and the way the keel is ballasted, so to speak, enable the bird to remain for hours in constant flight without apparently experiencing the least fatigue. Swallows are often seen resting on telegraph wires, but I have never seen a Swift perch on any support outside a chimney. At night and during such part of the day as is given up to rest, the bird supports itself in chimneys by clinging to projections or crevices. The stiff, sharp-pointed tail feathers aid greatly in supporting it. Before the coming of the white man, hollow trees served as the roosting and nesting places of the Swifts.

There is no better practice for the eye than distinguishing swallows from Swifts, when both species are mingled in the air. The Swift's flight, though very powerful, suggests that of the bat, on account of the frequency of the wing strokes; the rapid beating of the wings ceases at intervals and the bird glides through the air or turns on set wings. Then the twinkling flight begins again. There are none of those long sweeping strokes with which the Barn Swallow cleaves the air. The tail of the Swift, when the bird is flying, generally appears short and cigar-shaped, or, if spread, it is fan-shaped, not forked like the tails of all the swallows.

The ordinary note of the Swift is a single sharp cry, slowly or rapidly repeated; it is characteristic of warm summer evenings when the birds fly about the houses in twos or threes, pursuing each other and uttering this note staccato. A pretty sight at this time is the Swift sailing with wings raised above the body, in the position of our common pigeon just before alighting; the Swift assumes the same attitude above the chimney, poising a moment before he drops into the flue.

Early in September the Swifts leave the North, and may be seen high overhead flying southward; unlike many of our small birds, they migrate by day, their powers of flight protecting them from the birds of prey which are such a menace to the smaller birds.