The Natural History of Selborne 285 



eggs, which no doubt had been forced out of those insects by 

 the action of swallowing. 



Now as it appears that this bird, which is so well known 

 to practise incubation, is formed in a similar manner with 

 cuckoos, Monsieur Herissant's conjecture, that cuckoos are 

 incapable of incubation from the disposition of their intestines, 

 seems to fall to the ground ; and we are still at a loss for the 

 cause of that strange and singular peculiarity in the instance 

 of the cuculus canorus. 



We found the case to be the same with the ring-tail hawk, 

 in respect to formation ; and, as far as I can recollect, with 

 the swift; and probably it is so with many more sorts of 

 birds that are not granivorous. I am, &c. 



