THE LIFE-HISTORY OF BIRDS 273 



white feathers are wanting, but a white throat band is assumed 

 after the nuptial dress is discarded. 



The crimson patches in the plumage of our British Wood- 

 peckers is, in this connection, no less interesting. Thus, in the 

 Great-spotted Woodpecker the male — there is no special nuptial 

 dress — has a crimson nape, while the female has no such badge. 

 But young birds of both sexes, in their first year, have a patch 

 of red on the crown. In the Lesser-spotted Woodpecker the 

 male has the crimson on the crown instead of the nape, while 

 the female has white in place of the crimson. The young birds, 

 however, resemble those of the Greater-spotted species in having 

 the crown crimson, though in the females this colour is confined 

 to the forepart of the crown. Finally, in the Green Wood- 

 pecker the crown and nape feathers are crimson in both sexes, 

 though this colour is less vivid in the females ; while in the 

 young birds crimson appears only on the tips of the occipital 

 feathers. 



From this it would seem that in the life-histories of these 

 three species we have an insight into a very interesting phase 

 of evolution, one in which a character, probably first acquired 

 by the male, has become, as is so often the case, transferred 

 to the female, and to the young of both sexes. The Green 

 Woodpecker serves as a case in point, but here the female and 

 young birds have as yet only imperfectly assumed this feature. 

 The evidence seems to show that the two first-named species 

 in like manner assumed the vivid colour patches of the male 

 which were transmitted both to the adult female and to the 

 young. Later, apparently, evolution favoured the development 

 of a differentiation between the sexes which is being acquired, 

 or being transmitted, perhaps we should say, to the young 

 females, inasmuch as these in the Lesser-spotted species now 

 have the red confined to the forepart of the crown. Further- 

 more, the crimson crown was apparently common to adults of 

 all three species. To-day the Greater-spotted species has re- 

 duced this colour to a patch on the nape, while, as we might 

 expect, the young birds still pass through the originally adult 

 condition. Thus the colour, in its evolution, is acquired first by 

 the males, then by the females, and lastly by the young, possibly 

 beginning with the young male. And as the young are the 

 last to acquire new characters, so they are the last to lose old 



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