THE ELEVENTH FAMILY OF THE FISSIROSTRAL PICARIAN BIRDS.
THE SWIFTS (Cypselidæ).
These birds, with the Humming-birds, are separated from the other Fissirostral Picariæ by many anatomical characters, the chief being the arrangement of the feather-tracts on the body, which are quite peculiar; the muscles are also unlike those of the other families, and hence these two groups are often divided off by modern naturalists under the name of Macrochires.[285]
THE COMMON SWIFT (Cypselus apus).[286]
In the beginning of May the Common Swift comes to Great Britain and the rest of Europe, after passing his winter sojourn in South Africa. He is one of the latest arrivals, as he comes only when summer has fairly begun and fine weather is pretty well assured; again, in autumn, he is almost the first of the summer migrants to take his departure, and the absence of the Swifts from their accustomed haunts is a sure sign of the approach of the fall of the year. So incumbent does this early migration seem to be upon the species, that the Swifts have been known to leave their young to perish of starvation rather than delay their departure if cold weather suddenly approaches. All birds appear to have at times a failure of instinct, and the Swift is no exception to the rule, for sometimes they are caught in some cold weather on their arrival, and it is not uncommon to find them benumbed with cold, and fluttering helplessly or even lying dead on the ground. In this latter position they are peculiarly helpless, their little legs being unable to raise them so as to give them the proper momentum to rise into the air again, while their long wings are much in the way, and only assist in their entire discomfiture. The home of the Swift, then, is in the air, and here his evolutions are most rapid, and performed with extreme quickness and yet with consummate ease. For his breeding home he often selects water-spouts on lofty buildings, such as the English cathedrals, or else places his nest under the roofs of houses, to the edge of which he is able to shuffle, and then to launch himself suddenly down, after which his course is easy. In the evening there is generally a little gathering of Swifts together, when they fly screaming round and round the buildings in which their nests have been placed, separating again for a few moments to rejoin in an excited flock, which passes with incredible swiftness and much noise round the edges of the towers or homesteads. When about to migrate, however, they are silent, and the flocks which may be seen coursing along the sides of the downs in the southern counties of England in August utter no sound, as if impressed with the gravity of the long journey they are about to undertake.
COMMON SWIFT.
Macgillivray describes the nest of the Common Swift as follows:—“It is very rudely constructed, flattened, about six inches in diameter and half an inch thick; composed of particles of Aira cæspitosa, straws of oats, wheat, and grasses, intermixed with fibrous roots, moss, wool, cotton, hair, and feathers of the domestic fowl, partridge, and rook. These materials are confusedly felted and agglutinated, the glueing matter being of a gelatinous, not of a resinous, nature, and in extremely thin shreds, which crackle, but do not readily burn, when flame is applied to them. There is, however, a small quantity of the membranous scales of the Scotch fir, together with some resinous matter, in one of these nests.” The eggs are generally two in number, of a long oval shape, and entirely white.
TREE SWIFT.
