COURTSHIP IN BIRDS 257 



who can doubt that birds can not only identify 

 their own species with ease no matter how poorly 

 marked, but can pick out even their own off- 

 spring from others'? Does a Chinese woman 

 have any difficulty in recognizing her own off- 

 spring in a group of hundreds, all sinularl) 

 dressed and looking alike as peas to our un- 

 trained eyes? Or, to bring the matter nearer 

 home, watch a mother enter a schoolyard in 

 which a hundred small children all of the same 

 age and dress are playing. She picks out her own 

 child, brushes its dress and wipes its nose with 

 a perfect certainty of conviction as to its identi- 

 fication, but if asked for the field marks, is un- 

 able to give them. 



That the brilliant colors and markings of birds 

 are of use in courtship and that many of them are 

 the slow result of sexual selection seems to me to 

 be a reasonable supposition because the male bird 

 in courtship always displays these colors and 

 markings to the best advantage. Where two or 

 more males, as is often the case, are eagerly 

 doing their best in display it would seem natural 

 that the one who makes the most display is more 



