120 NATURAL HISTORY OF SELBORNE. 



swallow tribe, which increases prodigiously as the summer 

 advances : and I saw, at the time mentioned, many 

 hundreds of young wagtails on the banks of the Cherwell, 

 which almost covered the meadows. If the matter appears 

 as you say in the other species, may it not be owing to the 

 dams being engaged in incubation, while the young are 

 concealed by the leaves 1 



Many times have I had the curiosity to open the 

 stomachs of woodcocks and snipes ; but nothing ever 

 occurred that helped to explain to me what their subsist- 

 ence might be : all that I could ever find was a soft mucus, 

 among which lay many pellucid small gravels. 



LETTER IV. 



SELBORNE, Feb. 19^, 1770. 



YOUR observation that u the cuckoo does not deposit its 

 egg indiscriminately in the nest of the first bird that comes 

 in its way, but probably looks out a nurse in some degree 

 . congenerous, with whom to intrust its young," is perfectly 

 new to me ; and struck me so forcibly, that I naturally fell 

 into a train of thought that led me to consider whether the 

 fact was so, and what reason there was for it. When I 

 came to recollect and inquire, I could not find that any 

 cuckoo had ever been seen in these parts, except in the nest 

 of the wagtail, the hedge-sparrow, the titlark, the white- 

 throat, and the red-breast, all soft-billed insectivorous birds. 

 The excellent Mr. Willughby mentions the nest of the 

 palumbus (ring-dove), and of the fringilla (chaffinch), birds 

 that subsist on acorns and grains, and such hard food ; but 



