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 hippoboscae 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 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 British hirundines; and indeed from all other known birds, the hirundo melba, 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. (* John Antony Scopoli, of Carni
