IXII.] 



OF SELBORNE. 



181 



their way ; but not with that vehemence and fury that swallows 

 express on the same occasion. They are out all day long in wet 

 days, feeding about, and disregarding still rain : from whence 

 two things may be gathered : first, that many insects abide 

 high in the air, even in rain ; and next, that the feathers of these 

 birds must be well preened to resist so much wet. Windy, and 

 particularly windy weather with heavy showers, they dislike ; 

 and on such days withdraw, and are scarce ever seen. 



There is a circumstance repecting 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 

 Mrundines 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 before their con- 

 geners bring out their second broods. We may here remark, 

 that, as swifts breed but once in a summer, and only two at a 

 time, and the other hirundines twice, the latter, who lay from 

 four to six eggs, increase at an average five times as fast as the 

 former. 



But in nothing are swifts more singular than in their early 

 retreat. They retire, as to the main body of them, by the 10th 

 of August, and sometimes a few days sooner : and every 

 straggler invariably withdraws by the 20th, while their con- 

 geners, 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 



