SEX OF BIRDS. 
131 
but just begin to show themselves, and others are apparently 
thinner than usual ; as the whitethroat, the blackcap, the red- 
start, the flycatcher. T well remember that after the very severe 
spring in the year 1739-40 summer birds of passage were very 
scarce. They come probably hither with a south-east wind, or 
when it blows between those points ; but in that unfavourable 
year the winds blowed the whole spring and summer through 
from the opposite quarters. And yet amidst all these disadvan- 
tages two swallows, as I mentioned in my last, appeared this year 
as early as the eleventh of April amidst frost and snow ; but they 
withdrew again for a time. 
I am not pleased to find that some people seem so little satis- 
fied with Scopoii's new publication ;* there is room to expect 
great things from the hands of that man, who is a good naturalist : 
and one would think that a history of the birds of so distant and 
southern a region as Carniola would be new and interesting. I 
could wish to see that work, and hope to get it sent down. Dr» 
Scopoli is physician to the wretches that v/ork in the quicksilver 
mines of that district. 
When you talked of keeping a reed-sparrow, and giving it 
seeds, I could not help wondering ; becanse the reed-sparrow 
which I mentioned to you (passer arundinaceus minor Raii) is a 
soft-billed bird ; and most probably migrates hence before win- 
ter ; whereas the bird you kept (passer torquatus Raii) abides ail 
the year, and is a thick-billed bird. I question wrhether the lat- 
ter be much of a songster ; but in this matter I want to be better 
informed. The former has a variety of hurrying notes, and sings 
all night. Some part of the song of the former, I suspect, is 
attributed to the latter. We have plenty of the soft-billed sort ; 
which Mr. Pennant had entirely left out of his British Zoology, 
till I reminded him of his omission. See British Zoology last 
published, p. I6.t 
I have somewhat to advance on the diflferent manners in 
which different birds fly and walk ; but as this is a subject that 
I have not enough considered, and is of such a nature as not to 
be contained in a small space, I shall say nothing further about 
it at present.]: 
No doubt the reason why the sex of birds in their first plum- 
age is so difficult to be distinguished is, as you say, " because 
* This work he calls his Annus Primus Historico Naturalis- 
t See letter xxv. to Mr. Pennant, 
t See letter xlii to Mr. Barrington, 
K 2 
