SWIFTS. 171 



Windy, and j articularly windy weather with heavy showers, 

 they dislike, and on such days withdraw, and are scarcely ever 

 seen. 



There is a circumstance respecting the ^ colour of swifts, 

 which seems not to be unworthy our attention. When they 

 arrive in the spring, they are all over of a glossy dark soot 

 colour, except their chins, which are white ; but, by being all 

 day long in the sun and air, they become quite weather-beaten 

 and bleached before they depart, and yet they return glossy 

 again in the spring. Now if they pursue the sun into lower 

 latitudes, as some suppose, in order to enjoy a perpetual 

 summer, why do they not return bleached ? Do they not 

 rather, perhaps, retire to rest for a season, and at that juncture 

 moult and change their feathers, since all other birds are 

 known to moult soon after the season of breeding ? * 



Swifts are very anomalous in many particulars, dissenting 

 from all their congeners, not only in the number of their 

 young, but in breeding but once in a summer ; whereas all 

 the other British hirundines breed invariably twice. It is past 

 all doubt that swifts can breed but once, since they withdraw 

 in a short time after the flight of their young, and some time 



naturalists have lately had a controversy. " Last summer," says he, " 1 

 brought up by hand a turtle dove, which I accustomed to ily about my 

 room, till within this last month, at all times, except at night. Invariably 

 when I had it sitting on my hand, it would begin pluming itself, 

 (particularly while in moult, which was for about four months,) and, at 

 such times, it was curious to see it apply its bill to the gland, or nipple 

 just above its tail, and, by pincing it, procure something, though 1 

 could never discover what. On withdrawing its bill, it always stretched 

 out its neck, and twisted its head about in the strangest manner, with its 

 eyes shut, and the bill opening and shutting, as if in the act of chewing 

 something which put it in pain, but which I always considered was for 

 the purpose of spreading, or allowing the substance procured to circulate 

 to all parts of the bill. This operation lasted about^twelve seconds, and 

 then it immediately applied it, quickly, to only three or four different 

 parts of its plumage at a time, and, at its pleasure, easily enough, all over 

 its head and neck, by rubbing them on such parts as were within a 

 convenient distance ; for who ever saw a bird, particularly a duck, wash 

 itself, without observing it rub its head and neck on its back, or the 

 shoulders of its wings ? This I have seen it do at least ten times in as 

 many minutes on my hand ; but confess, I could never detect what it 

 was it procured from the gland for the purpose of spreading it over its 

 plumage, though I could distinctly see it pinch the nipple." ED. 



* The probability is, that these birds have just arrived in this country 

 after they have undergone the vernal moult. Birds differ considerably 

 in colour before the renewal of their plumage ; and that they are in this 

 state before taking their departure there can be little doubt, as they have 

 not yet been subjected to the autumnal moult. ED. 



