360 The Descent of Man. Taut II 



finch {Cardutlis tlegans), for I am assured by Mr. J. Jenner Weii 

 that the birdcatchers can distinguish the males by their slightly 

 longer beaks. The flocks of males are often found feeding on 

 the seeds of the teazle (Dipsacus), which they can reach with 

 their elongated beaks, whilst the females more commonly feed 

 on the seeds of the betony or Scrophularia. "With a slight 

 difference of this kind as a foundation, we can see how the beaks 

 of the two sexes might be made to differ greatly through natural 

 selection. In some of the above cases, however, it is possible 

 that the beaks of the males may have been first modified in 

 relation to their contests with other males; and that this 

 afterwards led to slightly changed habits of life. 



Law of Jiattle. — Almost all male birds are extremely pug- 

 nacious, using their beaks, wings, and legs fur fighting together. 

 We see this every spring with our robins and sparrows. The 

 smallest of all birds, namely the humming-bird, is one of the 

 most quarrelsome. Mr. Gosso* describes a battle in which a 

 pair seized hold of each other's beaks, and whirled round and 

 round, till they almost fell to the ground ; an 1 M. Montes de 

 Oca, in speaking of another genus of humming-bird, says that 

 two males rarely meet without a fierce aerial encounter : when 

 kept in cages " their fighting has mostly ended in the splitting of 

 " the tongue of one of the two, which then surely dies from 

 " being unable to feed."* With Waders, the males of the 

 common water-hen ( G-alUnula cMoropua) " when pairing, fight 

 " violently for the females: they stand nearly upright in the 

 " water and strike with their feet." Two were seen to be thus 

 engaged for half an hour, until one got hold of the head of the 

 other, which would have been killed, had not the observer 

 interfered ; the female all the time looking on as a quiet spec- 

 tator.^ Mr. Blyth informs me that the males of an allied bird 

 (Oulticrex cristatus) are a third larger than the females, and are 

 so pugnacious during the breeding- season, that they are kept by 

 the natives of Eastern Bengal for the sake of fighting. Various 

 otlier birds are kept in India for the same purpose, for instance, 

 the bulbuls (^Pycnonotus hxmorrhous) which " fight with great 

 •' spirit."" 



The polygamous ruff {Much ten piifpiax, fig. 37) is notorious 

 for hie extreme pugnacity ; and in tlie spring, the males, which 

 are considerably larger than the females, congregate day after 



' Quoted by Mr. Gould, 

 .Auction to the Trocliilidai. 

 0. 29. 



< Gonld, ibid. p. .'52. 

 W. ThompsoD. ' N;it, Hist, of 



