Chap. XIII.] LAW OF BATTLE. 41 



males drive away the weaker ones, snapping with their 

 huge beaks and giving heavy blows with their wings. 

 Male snipes fight together, "tugging and pushing each 

 other with their bills in the most curious manner ima<n- 

 nable." Some few species are believed never to fight ; this 

 is the case, according to Audubon, with one of the wood- 

 peckers of the United States (Plcus aicratus), although 

 "the hens are followed by even half a dozen of their gay 

 suitors." 9 



The males of many birds are larger than the females, 

 and this no doubt is an advantao; e to them in their bat- 

 ties with their rivals, and has been gained through sexual 

 selection. The difference in size between the two sexes is 

 carried to an extreme point in several Australian species ; 

 thus the male musk-duck (Biziura) and the male Cinclo- 

 ramphus cruralis (allied to our pipits) are by measure- 

 ment actually twice as large as their respective females. 1 ' 

 With many other birds the females are larger than the 

 males ; and as formerly remarked, the explanation often 

 given, namely, that the females have most of the work in 

 feeding their young, will not suffice. In some few cases, 

 as Ave shall hereafter see, the females apparently have ac- 

 quired their greater size and strength for the sake of con- 

 quering other females and obtaining possession of the 

 males. 



The males of many gallinaceous birds, especially of 

 the polygamous kinds, are furnished with special weapons 

 for fighting with their rivals, namely spurs, which can be 

 used with fearful effect. It has been recorded by a trust- 

 worthy writer 11 that in Derbyshire a kite struck at a 



9 ' Ornithological Biography,' vol. i. p. 191. For pelicans and snipes, 

 see vol. iii. pp. 381, 4*77. 



10 Gould, « Hand-book of Birds of Australia,' vol. i. p. 395 ; vol. Ii. p 

 883. . 



11 Mr. Hewitt in the 'Poultry Book by Tegetmeier,' 1866, p. 137. 



