106 THE NATURAL HISTORY [LETT. 



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 

 satisfied with Scopoli's new publication, " Annus Primus His- 

 torico-Naturalis." There is room to expect great things from 

 the hands of that man, who is a good naturalist : and one would 

 think that an history of the birds of so distant and southern a 

 region as Carniola would be new and interesting. I could wish 

 to see the work, and hope to get it sent down. Dr. Scopoli is 

 physician to the wretches that work in the quicksilver mines 

 of that district. 



When you talked of keeping a reed-sparrow, and giving it 

 seeds, I could not help wondering ; because the reed-sparrow 

 which I mentioned to you (Passer arundinaceus minor Raii) 1 is 

 a soft-billed bird, and most probably migrates hence before 

 winter ; whereas the bird you kept (Passer torquatus Eaii) 2 abides 

 all the year, and is a thick-billed bird. I question whether the 

 latter 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. 3 



I have somewhat to advance on the different 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. 4 



No doubt the reason why the sex of birds in their first plumage 

 is so difficult to be distinguished is, as you say, " because they 

 are not to pair and discharge their parental functions till the 

 ensuing spring." As colours seem to be the chief external sexual 

 distinction in many birds, these colours do not take place till 

 sexual attachments commence. The case is the same with 



1 Sedge-warbler, Salicuria phragmitit, Selby. 

 ! Reed-bunting, Emberiza gchtenicltu, Linn. 



3 See Letter xxvi., to Mr. Pennant, August 30, 1769. 



4 See Letter Ixxxiv., to Mr. Harrington, August 7, 1778. 



