18 How to Sex Cage Birds. 



betray the fact that the}' are not adult. As all those who have 

 hand-reared nestlings are aware, the gape of young birds is very 

 broad, and this infantile type of bill takes a long time to modify 

 into the far more slender adult form ; it certainly is not perfected 

 after the completion of the first moult in the soft-billed birds, as I 

 proved in the case of such as I hand-reared, or which were bred in 

 my aviaries. 



The Barred Warbler {Sylvia nisoria). 



Although a somewhat rare visitor to our islands, this bird has 

 been exhibited at London shows, and therefore should be noted. 

 The female is slightly browner than the male, and has fewer trans- 

 verse bars, those which it possesses being also less defined during 

 the summer, though not in the winter. 



The Garden Warbler (Sylvia hortensis). 

 During the summer the female is slightly paler than the male, 

 but in winter they are much alike in plumage. 



The Dartford Warbler (Sylvia undata). 

 In the female the under parts are paler than in the male. 



The Golden-crested Wren (Regulus cristatus). 



In this charming little Warbler the hen is less brightly coloured 

 than the cock, the yellow crest-like streak clouded with brownish, 

 and with narrower black borders. I have never seen the so-called 

 crest erected, though I have carefully watched pairs of this species 

 from time to time in my garden, and therefore I doubt the correct- 

 ness of illustrations which show this bird with a true crest. 



The Fire-crested Wren (Regulus ignicapillus). 

 The female is duller in colouring than the male, and its yellow 

 crest-patch is paler. 



The Yellow-browed Warbler (Phylloscopus super ciliosus). 



This pretty little bird appears to be on the increase as a visitor 

 to the British Islands. _ I have once seen it in the autumn in my 

 suburban garden. The plumage of the sexes is extremely similar. 



The Chiffchaff (Phylloscopus rufus). 



In this species the sexes are remarkably alike in colouring, the 

 shorter bill of the hen being the best character for distinguishing it. 



The Willow-Warbler (Phylloscopus trochilus). 

 Here again the sexes are very similar in colouring, no constant 

 differences having been pointed out. 



The Wood-Warbler (Phylloscopus sibilatrix). 

 No difference of plumage has been recorded in the sexes. 



