200 NATURAL HISTORY OF SELBORNE 



be in a very uneasy situation during the business of incuba- 

 tion; yet the test will be to examine whether birds that 

 are actually known to sit for certain are not formed in a 

 similar manner. This inquiry I proposed to myself to make 

 with a fern-owl, or goat-sucker, as soon as opportunity 

 offered : because, if their formation proves the same, the 

 reason for incapacity in the cuckoo will be allowed to have 

 been taken up somewhat hastily. 



Not long after a fern-owl was procured, which, from its 

 habit and shape, we suspected might resemble the cuckoo in 

 its internal construction. Nor were our suspicions ill- 

 grounded ; for, upon the dissection, the crop, or craw, also 

 lay behind the sternum, immediately on the viscera, between 

 them and the skin of the belly. It was bulky, and stuffed 

 hard with large phalcence, moths of several sorts, and their 

 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 Cticulus 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. 



