144 NATURAL HISTORY OF SELBORNE. 



mentioned to you (Passer arundinaceus minor Rait) is a soft-billed 

 bird ; and most probably migrates hence before winter ; whereas 

 the bird you kept (Passer torquatus Rait) 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. See " British Zoology " last published, p. 16. 



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. 



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 distinc- 

 tion in many birds, these colours do not take place till sexual 

 attachments begin to obtain. And the case is the same in 

 quadrupeds ; among whom, in their younger days, the sexes differ 

 but little: but, as they advance to maturity, horns and shaggy 

 manes, beards and brawny necks, etc., etc., strongly discriminate 

 the male from the female. We may instance still farther in our 

 own species, where a beard and stronger features are usually cha- 

 racteristic of the male sex : but this sexual diversity does not take 

 place in earlier life ; for a beautiful youth shall be so like a beautiful 

 girl that the difference shall not be discernible j 



" Quern si puellarum insereres chore, 

 Mire sagaces falleret hospites 

 Discrimen obscurum, solutis 

 Crinibus, ambiguoque vultu." 



HOR. ODES. II. od. 5-21, p. 13;', orig. edit. 



