138 NATURAL HISTORY OF SELBORNE. 



withstanding so many young are hatched daily. Sure I am that 

 it is far otherwise with respect to the 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 con- 

 cealed by the leaves ? 



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 subsistence might be : all that I could 

 ever find was a soft mucus, among which lay many pellucid small 

 gravels. 1 



I am, etc. 



NOTE TO LETTER III. 



1 Upon examining patches of mud on which I have flushed woodcocks and 

 snipes, I have found them riddled with small perforations, clearly made by the 

 bills of the birds, which must have been seeking some insects or worms therein. 



LETTER IV. 



SELBORNE, Feb. \tyh, 1770. 



DEAR SIR, Your observation that "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 congene- 

 rous, 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 redbreast, all soft-billed insectivorous birds. 

 The excellent Mr. Willughby mentions the nest of the Palumbus 



