93 



which was observed in the wild state to get continually whiter, 

 and he ultimately died from natural causes, so that his constitu- 

 tion could not have been good. At the same time he was the best 

 fighter of the neighbourhood, so that if a hen Blackbird wanted 

 a mate it had to be this bird or none at all. Thus if his colour 

 had been hereditary, he would have been the founder of a pied 

 strain. It is rather significant that the very colours indicative of 

 constitutional disturbance, such as white and black in brown 

 birds, and yellow in green birds, should also be those so often 

 constituting an ornamental appearance in the males. It looks as 

 if masculine beauty were acquired at some cost constitutionally, 

 just as among ourselves the golden hair and rosy cheeks of the 

 typical beauty do not necessary mean a good constitution, but 

 rather indicate one less resistant to some unfavourable influence 

 than the brunette type. 



There is evidence that in some cases the white colouration 

 is becoming common in nature. In some wild species of Herons 

 which frequent the sea-shore, white varieties are quite common, 

 and the fact may be here recalled that there are more species 

 among the Herons constantly white than in any other family of 

 birds. Here, then, the white varieties, whether by the force of 

 heredity or by being more courageous or more cunning than 

 their neighbours, have evidently managed to established them- 

 selves permanently. I may mention that some of the above 

 variable Herons are white when young, and grey when adult, 

 recalling the case of the non-permanent albinism above alluded 

 to. 



Of course there is also the possibility of white or pied birds 

 being more attractive to the hens than those of the ordinary 

 colour, but there is at present so little evidence that the prefer- 

 ences of hen birds have anything to do with the male's appearance* 

 that we cannot invoke the aid of sexual selection in explanation 

 of colour peculiarities with the same confidence as we can natural 

 selection or the force of prepotent heredity. 



* Experience teaches me that with many species of birds (as also in genus Homo) the 

 female is the choosing party, and that other things being equal she goes in for appearance, 

 but vigour before anything else appears to actuate her choice, for if another male be 

 present lacking the brilliance of the weaker bird but very vigorous, she chooses the 

 vigorous bird.— Ed.] 



