44 SEXUAL SELECTION: BIRDS. [Part II. 



ing represented by mere knobs or rudiments in the female ; 

 but tne females of the Java peacock (Pavo millions) and, 

 as I am informed by Mr. Blyth, of the small fire-backed 

 pheasant {Euplocamus erythropthalmus) possess spurs. 

 In Galloperdix it is usual for the males to have two spurs, 

 and for the females to have only one on each leg. 15 Hence 

 spurs may safely be considered as a masculine character, 

 though occasionally transferred in a greater or less degree 

 to the females. Like most other secondary sexual charac- 

 ters, the spurs are highly variable both in number and de- 

 velopment in the same species. 



Various birds hav.e spurs on their wings. But the 

 Egyptian goose ( Chenalopex JEgyptiacus) has only " bare 

 obtuse knobs," and these probably show us the first steps 

 by which true spurs have been developed in other allied 

 birds. In the spur-winged goose (Plectropterus gamben- 

 szs), the males have much larger spurs than the females ; 

 and they use them, as I am informed by Mr. Bartlett, in 

 fighting together, so that, in this case, the wing-spurs serve 

 as sexual weapons ; but according to Livingstone, they are 

 chiefly used in the defence of the young. The Palamedea 

 (Fig. 38) is armed with a pair of spurs on each wing ; and 

 these are such formidable weapons that a single blow has 

 driven a dog howling away. But it does not appear that 

 the spurs in this case, or in that of some of the spur-winged 

 rails, are larger in the male than in the female. 16 In cer- 

 tain plovers, however, the wing- spurs must be considered 

 as a sexual character. Thus in the male of our common 

 peewit (Vcmellus cristatus) the tubercle on. the shouldei 



15 Jerdon, 'Birds of India:' on Ithaginis, voL iii. p. 523; on Gallo- 

 perdix, p. 541. 



10 For the Egyptian goose, see Macgillivra"y, ' British Birds,' vol. iv. 

 p. 639. For Plectropterus, ' Livingstone's Travels,' p. 254. For Pala- 

 medea, Brehm's ' Thierleben,' B. iv. s. 740. See also on this bird Azara, 

 'Voyages dans l'Amerique mend.' torn. iv. 1809, pp. 1*79, 253. 



