366 CYPSELID.E. 



The Swift commonly chooses its nesting-place in holes 

 under the eaves of houses, in church-towers and other build- 

 ings, as well as crevices in rocks, and will not disdain a 

 cranny in the face of a chalk-pit. In countries not offering 

 such accommodation it uses hollow trees, and it has been 

 recorded as so doing in England, though perhaps on insuf- 

 ficient authority. It has been also said to remain for hours 

 in its retreat on windy days, motionless and in the dark, but 

 this assertion is certainly not generally, if ever, true ; for 

 when insects are to be had the bird is regardless of weather, 

 and its occasional withdrawal from observation during storms 

 can with reason be accounted for by the vast distances to 

 which its speed of flight enables it to range without difficulty, 

 in quest of prey that may be more abundant away from its 

 home. Ordinarily it is seen darting rapidly or wheeling in 

 circles while in pursuit of its insect-food ; at one time sailing 

 with ease and pleasure at an elevation where it is scarcely 

 perceivable, and at another passing the spectator, in Gilbert 

 White's words, " with the almost inconceivable swiftness of a 

 meteor." Little, or perhaps nothing, is known of the means 

 whereby birds in their rapid career are able to adjust their 

 sight, so as to avoid obstacles and make their captures, but 

 it is obvious from the most cursory observation, that few can 

 more completely control their visual organs than Swifts, though 

 Swallows must approach them veiw nearly in this respect.* 



The nest is formed of bits of straw, dry grass and a few 

 feathers, all collected on the wing, and glued firmly together 

 by the mucous secretions of the birdt so as to become a hard 



* Mr. 0. Clapton says (Mag. Nat. Hist. v. p. 203) that at Hastings he saw a 

 Swift dash itself against a wall, when it was picked up stunned, and almost 

 immediately died in his hand. He could not perceive any defect in its eyes, but 

 he mentions that it was infested with parasites, which may well have impaired 

 its vision. Mr. Watters also mentions a Swift in his possession, obtained by 

 striking against a man's hat in a Dublin street and falling senseless at his side. 



t Macgillivray's figure (Br. B. pi. xxii. fig. 5) of the digestive organs of the 

 Swift shews the enormous size of its salivary glands, situated between the rami 

 of the lower jaw, whence these secretions arise, but it is doubtful whether they 

 may not be supplemented by others proceeding from the proventriculus. Such 

 at any rate, according to Home (Phil. Trans. 1817, p. 3.32, pi. xvi.), appears 

 to be the case in birds of the allied genus Collocalia, which, though commonly 



