310 THE STRUCTURE AND LIFE OF BIRDS chap. 



danger to each other before the females. The Ruffs, 

 who, unhappily, no longer breed in England, supply the 

 best instance of this. They have regular places at 

 which they, assemble, known to fowlers by the grass 

 being trampled down. Here day after day they con- 

 gregate and go through their fantastic performance. 



Fighting pure and simple unaccompanied by antics 

 is common. Humming-birds are said to fight des- 

 perately. The males of the Common Waterhen have 

 great battles, standing nearly upright in the water, 

 and fighting with their feet. Robins are great fighters. 

 The males of gallinaceous birds are often very pug- 

 nacious and in their spurs they have a formidable 

 weapon. The courage and ferocity of the Gamecock is 

 proverbial. As a rule it is among polygamous species 

 that we find the combats most desperate and the 

 antics most elaborate. 



Theories to explain these Phenomena. 



Darwin was first in the field with a definite 

 theory, to which he gave the name of Sexual Selection. 

 The cock-birds fought and the hen-birds were the 

 prizes. There is no doubt that this theory rests on a 

 foundation of fact. Selection by battle goes on in 

 many classes of animals, notably among deer and 

 cattle. But an explanation of the brilliant plumage 

 was more difficult to find. The theory which we owe 

 to him is very ingenious and plausible, but the evidence 

 on which it rests is insufficient. The female bird, he 

 maintained, selected the handsomest male bird, or the 

 best singer, or the one that performed the most strik- 



