LETTER LII 



TO THE SAME 



SELBORNE, Sept. yh, 1781. 



I HAVE just met with a circumstance respecting swifts, 

 which furnishes an exception to the whole tenor of my 

 observations ever since I have bestowed any attention on 

 that species of hirundines. Our swifts, in general, withdrew 

 this year about the first day of August, all save one pair, 

 which in two or three days was reduced to a single bird. 

 The perseverance of this individual made me suspect that 

 the strongest of motives, that of an attachment to her 

 young, could alone occasion so late a stay. I watched 

 therefore till the twenty-fourth of August, and then dis- 

 covered that, under the eaves of the church, she attended 

 upon two young, which were fledged, and now put out 

 their white chins from a crevice. These remained till the 

 twenty-seventh, looking more alert every day, and seeming 

 to long to be on the wing. After this day they were 

 missing at once ; nor could I ever observe them with 

 their dam coursing round the church in the act of learning 

 to fly, as the first broods evidently do. On the thirty-first 

 I caused the eaves to be searched, but we found in the 

 nest only two callow, dead, stinking swifts, on which a 

 second nest had been formed. This double nest was full 

 of the black shining cases of the hippobosca hirundinis* 



The following remarks on this unusual incident are 

 obvious. The first is, that though it may be disagreeable 

 to swifts to remain beyond the beginning of August, yet 



1 A parasitic fly, now known as Stcnoptcryx hirundinis, which infests the 

 bodies and nests of birds of the swallow tribe. [R. I. P.] 



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