94 UNDER THE OPEN SKY 



and take to cleaning from the bark of the 

 white oak the little bugs that infest it. 

 Even when feeding at the flowers he prob- 

 ably gets as much of his food from the in- 

 sects as from the nectar. 



WHERE MARRIAGE DEPENDS ON BEAUTY 



But perhaps the strangest part of the 

 transformation is yet to be told. Living 

 as they do among bright-colored flowers, 

 the hummers have become gradually more 

 aesthetic in their tastes and more fastidious 

 in the demand for beauty in their mates. 

 The dull ones failed more and more com- 

 pletely in the matrimonial market, until 

 now only the brightest members are left to 

 tell the tale, — that is, the brightest males, 

 for here, as in so many cases, the females 

 must sit on an open nest. The dainty bed 

 covered with its protective crust of lichens, 

 in which the female rears her tiny brood, is 

 so open that a metallic-green mother would 

 invite her own destruction. It is doubtless 

 an added influence in the bright color change 

 that the quicker movements of the male 



