24 A FIRST LIST OF THE BIIIDS 



As regards the younger birds, the case is not quite equally 

 clear, either they are variable or else it may be that owing to 

 the difficulty of discriminating- the sexes in very young- birds, 

 some of our specimens have been wrongly sexed. This much, 

 however, seems to be quite clear, viz., that both young males 

 and young females when about half grown have both upper 

 and lower mandibles black or brownish black. The bills of the 

 males not uncommonly exhibiting more or less of a reddish 

 brown tin ere. It also appears certain that the great majority 

 of the youngest males have both mandibles (and not as Mr. 

 Blyth says the upper mandible only) red or reddish orange and 

 also that this color changes a little later into black or nearly 

 black. We have numerous such very young males sexed by 

 dissection, and others again somewhat older, shewing the change 

 from the red to black or blackish brown, and then again others 

 clearly considerably older shewing the change of this latter color 

 on the upper mandible into the vermilion red of the adult. 



These are clearly the normal changes in the young male ; first 

 both mandibles reddish orange or orange horny ; then both 

 mandibles black or blackish brown; then the upper mandible 

 vermillion red, and lower mandible blackish brown, or blackish 

 horny, or horny brown. 



The first change has been actually witnessed. Mr. De Boep- 

 storff says (ante Vol. III., p. 264) : — " You will remember nam- 

 ing that young Palaeornis with the black bill for me. Now I got 

 that bird as a little one before its feathers were properly grown, 

 and its upper mandible was then red ; on this account I thought 

 it was a male, but after a short time I found the red, or reddish 

 color of the bill, which was not unlike that of the same part 

 the adult male change into black." 



On the other hand, I believe, that exceptions to this general 

 rule occur. I saw two birds taken from the nest which had 

 blackish dusky bills, one of which I at the time made out to be 

 a male, but as we have procured no second example as yet of 

 the quite nestling male with black bill, there may have been 

 an error in this case in the discrimination of the sex. 



I may here note that I have an almost perfectly adult male 

 with the lower mandible also red as Mr. Blyth remarks occa- 

 sionally happens. 



As regards the young females, of which I have some twenty 

 odd specimens, some of them apparently very young, I should 

 have been disposed to believe, that they had both mandibles 

 black ab ovo, but there is one single very young bird sexed as 

 a female by Mr. Davison which has the bill colored as in the 

 nestling male. It would seem, therefore, that either this parti- 

 cular specimen has been wrongly sexed, or that the young 



