262 THE NATURAL HISTORY 



I have only to add that were the bushes, which cover 

 some acres, and are not my own property, to be grubbed 

 and carefully examined, probably those late broods, and 

 perhaps the whole aggregate body of the house-martins 

 of this district, might be found there, in different secret 

 dormitories ; and that, so far from withdrawing into 

 warmer climes, it would appear that they never depart 

 three hundred yards from the village. 



LETTER LVI 



They who write on natural history cannot too frequently 

 advert to instinct, that wonderful limited faculty, which, 

 in some instances, raises the brute creation as it were 

 above reason, and in others leaves them so far below it. 

 Philosophers have defined instinct to be that secret 

 influence by which every species is impelled naturally to 

 pursue, at all times, the same way or track, without any 

 teaching or example ; whereas reason, without instruction, 

 would often vary and do that by many methods which 

 instinct effects by one alone. Now this maxim must be 

 taken in a qualified sense ; for there are instances in 

 which instinct does vary and conform to the circum- 

 stances of place and convenience. 



It has been remarked that every species of bird has a 

 mode of nidification peculiar to itself ; so that a school- 

 boy would at once pronounce on the sort of nest before 

 him. This is the case among fields and woods, and 

 wilds ; but, in the villages round London, where mosses 

 and gossamer, and cotton from vegetables, are hardly to 

 be found, the nest of the chaffinch has not that elegant 

 finished appearance, nor is it so beautifully studded with 

 lichens, as in a more rural district : and the wren is obliged 



