EGG OF THE CUCKOO. 
129 
If tliis severe season does not interrupt the regularity of tlie 
summer migrations, the blackcap will be here in two or three 
days. I wish it was in my power to procure you one of those 
songsters ; but I am no birdcatcher ; and so little used to birds 
in a cage, that I fear if I had one it would soon die for want of 
skill in feeding. 
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 publi- 
cation, p. 16 ? 
As to the matter of long-billed birds growing fatter in mode- 
rate frosts, I have no doubt within myself what should be the 
reason. The thriving at those times appears to me to arise alto- 
gether from the gentle check which the cold throws upon insen- 
sible 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 rab- 
bits 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 overbalances the repletion 
occasioned by a checked perspiration. I have observed, more- 
over, that some human constitutions are more inclined to plump- 
ness 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 v/onder, with good reason, that the hedge-sparrows, &c., 
can be induced at all to sit on the egg of the cuckoo without 
bemg scandalized at the vast disproportionate size of the suppo- 
sititious 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 shape- 
less stone instead of a nest full of eggs that have been with- 
K 
