SEXUAL SELECTION 469 



The polygamous ruff {Machetes pugnax, Fig. 87) is notori- 

 ous for his extreme pugnacity; and in the spFing, the males, 

 which are considerably larger than the females, congregate 

 day after day at a particular spot, where the females pro- 

 pose to lay their eggs. The fowlers discover these spots by 

 the turf being trampled somewhat bare. Here they fight 

 very much like game-cocks, seizing each other with their 

 beaks and striking with their wings. The great rufE of 

 feathers round the neck is then erected, and, according to 

 Col. Montagu, "sweeps the ground as a shield to defend the 

 more tender parts"; and this is the only instance known 

 to me, in the case of birds, of any structure serving as a 

 shield. The ruff of feathers, however, from its varied and 

 ricb colors, probably serves in chief part as an ornament. 

 Like most pugnacious birds, they seem always ready to 

 fight, and when closely confined often kill each other; but 

 Montagu observed that their pugnacity becomes greater 

 during the spring, when the long feathers on their necks 

 are fully developed; and at this period the least movement 

 by any one bird provokes a general battle.' Of the pug- 

 nacity of web-footed birds, two instances will suffice: in 

 Guiana "bloody fights occur during the breeding season 

 between the males of the wild musk-duck {Cairina mos- 

 chata); and where these fights have occurred the river is 

 covered for some distance with feathers." ' Birds which 

 seem ill-adapted for fighting engage in fierce conflicts; thus 

 the stronger males of the pelican drive away the weaker 

 ones, snapping with their huge beaks and giving heavy 

 blows with their wings. Male snipe fight together, "tug- 

 ging and pushing each other with their bills in the most 

 curious manner imaginable." Some few birds are believed 

 never to fight; this is the case, according to Audubon, with 

 one of the woodpeckers of the United States {Picus auratus), 



' Macgillivray, "Hist. Brit. Birds," vol. iv., 1852, pp. 177-181. 

 ' Sir B. SchombuTgk in " Journal of Bo;al Greographictd So<dol7," voL 

 ziii., 1843, p. 31. 



