But in nothing are swifts more singular than in their early retreat. They retire, as to the main body of them, by the 10th August, and sometimes a few days sooner; and every straggler invariably withdraws by the 20th, while their congeners, all of them, stay till the beginning of October—many of them all through that month, and some occasionally to the beginning of November. This early retreat is mysterious and wonderful, since that time is often the sweetest season in the year. But what is more extraordinary, they begin to retire still earlier in the most southerly parts of Andalusia, where they can be
in no ways influenced by any defect of heat, or, as one might suppose, failure of food. Are they regulated in their motions with us by a defect of food, or by a propensity to moulting, or by a disposition to rest after so rapid a life, or by what? This is one of those incidents in natural history that not only baffles our searches, but almost eludes our guesses!
These hirundines never perch on trees or roofs, and so never congregate with their congeners. They are fearless while haunting their nesting-places, and are not to be scared with a gun, and are often beaten down with poles and cudgels as they stoop to go under the eaves. Swifts are much infested with those pests to the genus called hippoboscœ hirundinis; and often wriggle and scratch themselves in their flight to get rid of that clinging annoyance.
Swifts are no songsters, and have only one harsh screaming note; yet there are ears to which it is not displeasing, from an agreeable association of ideas, since that note never occurs but in the most lovely summer weather.
They never can settle on the ground but through accident, and, when down, can hardly rise, on account of the shortness of their legs and the length of their wings; neither can they walk, but only crawl; but they have a strong grasp with their feet, by which they cling to walls. Their bodies being flat they can
enter a very narrow crevice; and where they cannot pass on their bellies they will turn up edgewise.
The particular formation of the foot discriminates the swift from all the British hirundines; and, indeed from all other known birds, the hirundo melba, or great white-bellied swift of Gibraltar, excepted; for it is so disposed as to carry “omnes quatuor digitos anticos”—all its four toes forward; besides, the least toe, which should be the back toe, consists of one bone alone, and the other three only of two apiece,—a construction most rare and peculiar, but nicely adapted to the purposes in which their feet are employed. This and some peculiarities attending the nostrils and under mandible have induced a discerning naturalist to suppose that this species might constitute a genus per se.
In London a party of swifts frequents the Tower, playing and feeding over the river just below the bridge; others haunt some of the churches of the Borough, next the fields, but do not venture, like the house-martin, into the close crowded part of the town.
The Swedes have bestowed a very pertinent name on this swallow, calling it “ring swala,” from the perpetual rings or circles that it takes round the scene of its nidification.
Swifts feed on coleoptera, or small beetles with hard cases over their wings, as well as on the softer insects,