128 
NATURAL HISTORY 
Was your reed-fparrow, which you kept in a cage, the thick- 
bilied reed-fparrow of the Zoology, p. 320; or was it the Icfs reed- 
fparrow of Rav, the fcdge-bird of Mr. Vcrinanfs lafl publication, 
p. 1 6 ? 
As to the matter of long-billed birds growing fatter in moderate 
frofts, I have no doubt within myfelf what fhould be the reafon. 
The thriving at thofe times appears to me to arife altogether from 
the gentle check which the cold throws upon infenfible perfpiration. 
The cafe is juft the fame with blackbirds, &c, ; and farmers and 
warreners obferve, the firft, that their hogs fat more kindly at fuch 
times, and the latter that their rabbits are never in fuch good cafe 
as in a gentle froft. But when frofts are fevere, and of long con- 
tinuance, the cafe is foon altered ; for then a want of food foon 
overbalances the repletion occafioned by a checked perfpiration. 
I have obferved, moreover, that fome human conflitutions are 
more inclined to plumpnefs in winter than in fummer. 
When birds come to fuiTer by fevere froft, I find that the firfb 
that fail and die are the redwing-fieldfares, and then the fong- 
thruflies. 
You wonder, with good reafon, that the hedge-fparrows, he. can 
be induced at all to fit on the egg of the cuckoo without being fcan- 
da'lized at the vaft difproportioned fize of the fuppofititioiis egg ; 
but the brute creation, I fuppofe, have very little idea of fize, 
colour, or number. For the common hen, I know, when the 
fury of incubation is on her, will fit on a fingle (hapelefs ftone in- 
ftead of a neft full of eggs that have been withdrawn : and, more- 
over, a hen-turkey, in the fame circumftances, would fit on in the 
empty neft till fhe periflied with hunger. 
I think the matter might eafily be determined whether a cuckoo 
lays one or two eggs, or more, in a feafon, by opening a female 
during 
