Swallow
a large family of swift, insectcatching, birds. In tests made recently by a French scientist, it has been definitely settled that the swallow is the swiftest of birds. One of them has been seen to make 210 feet a second, and at times even 290 feet was attained. At this rate the bird flies a mile in 18 seconds. Swallows have long, powerful wings, short, wide mouths, and small, weak feet with which they perch or cling but use scarce at all for walking. There are over eighty species. The tails of most species are deeply forked, hence the term "swallow-tailed" applied to an evening coat. Originally, of course, all swallows found nesting places in cliffs, caverns, old trees, and banks, living chiefly on insects and wintering in the tropics. The brownish gray bank swallow still nests in perpendicular cliffs of sand or clay, usually bordering a stream. Large colonies frequently occupy the same bank. The nest is made of grass and feathers about a yard from the entrance and shelters from four to six white eggs. The rough-winged swallow is a bird of somewhat similar appearance and habits, not infrequently building about bridges and railway trestles.
Three species, the tree swallow, the barn swallow, and the cliff or eave swallow, have steel-blue upper parts. The tree swallow is white beneath and nests like a martin in a tree or bird box. Its tail is slightly forked. The barn swallow has a deeply forked tail and chestnut under parts. It builds nests of mud and grasses, chiefly on beams inside of a barn or other building. This is the swallow that skims over the meadows turning this way and that way, up and down, with such marvelous grace and swiftness in its search for insects.
The eave swallow, with tail feathers of nearly equal length and reddish brown tail coverts, hovers in flocks on the muddy shores of a pond or puddle, making mud pellets with which to build a honeycomb of nests under the eaves of a nearby ban. Even though their nests be swept off repeatedly by the farmer's long pole, the eave swallows are not easily driven away. It would seem that they ought to be able to pay rent by catching insects. The cliff or cave swallow is a western species. It is one of the few birds that is working its way eastward. "The cliff swallow alone of all animated nature emigrates eastward," says Lowell. The three blue-backed species named frequently associate. A flock sitting on a telegraph wire may contain all three species, but they are distinguished readily by the shape of the tail and the color of the under parts. A fine cut on page 318 of Chapman's Manual makes the distinction plain. The return of the swallow is awaited eagerly in northern latitudes, but there is an old saying to the effect that "one swallow does not make a summer."