The Natural History of Se I borne 183 



Was your reed-sparrow, which you kept in a cage, the 

 thick-billed reed-sparrow of the " Zoology, " p. 320 ; or was it 

 the less reed-sparrow of Ray, the sedge-bird of Mr. Pennant's 

 last publication, p. 16 ? 



As to the matter of long-billed birds growing fatter in 

 moderate frosts, I have no doubt within myself what should 

 be the reason. The thriving at those times appears to me to 

 arise altogether from the gentle check which the cold throws 

 upon insensible perspiration. The case is just the same with 

 blackbirds, &c.; and farmers and warreners observe, the first, 

 that their hogs fat more kindly at such times, and the latter 

 that their rabbits are never in such good case as in a gentle 

 frost. But when frosts are severe, and of long continuance, 

 the case is soon altered ; for then a want of food soon over- 

 balances the repletion occasioned by a checked perspiration. 

 I have observed, moreover, that some human constitutions 

 are more inclined to plumpness in winter than in summer. 



When birds come to suffer by severe frost, I find that the 

 first that fail and die are the redwing-fieldfares, and then the 

 song-thrushes. 



You wonder, with good reason, that the hedge-sparrows, 

 &c., can be induced at all to sit on the egg of the cuckoo 

 without being scandalized at the vast disproportionate size of 

 the supposititious egg; but the brute creation, I suppose, have 

 very little idea of size, colour, or number. For the common 

 hen, I know, when the fury of incubation is on her, will sit on 

 a single shapeless stone instead of a nest full of eggs that 

 have been withdrawn : and, moreover, a hen turkey, in the 

 same circumstances, would sit on in the empty nest till she 

 perished with hunger. 1 



I think the matter might easily be determined whether a 



1 As a matter of fact, the egg of the cuckoo is scarcely larger than that 

 of the hedge-sparrows and chaffinches in whose nest the mother-bird lays : 

 but the young cuckoo is very voracious, and therefore soon outgrows its 

 small foster-brothers. Cuckoos have not been observed to lay in the nests 

 of birds whose eggs are larger than their own. Their most common host, 

 4 think, "is the meadow-pipit. ED, 



