158 NATURAL HISTORY 
If this severe season does not interrupt the reg- 
ularity of the 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 bird-catcher, 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 red 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 
sedgebird 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, é&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 overbalances 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 come to die are the redwing 
fieldfares, and then the song-thrushes. . 
You wonder, with good reason, that the hedge- 
sparrows, é&c., can be induced at all to sit on the 
egg of the cuckoo without being scandalized at the 
vast disproportioned size of the supposititious egg ; 
