BIBDB. 411 



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 {Cairinamo- 

 schata); and where these fights have occurred the " river is 

 covered for some distance with feathers." f 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 ima^nable." Some few birds are believed 

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

 one of the woodpeckers of the United States (Picu sau- 

 ratus), although *'the hens are followed by even half a 

 dozen of their gay suitors." % 



The males of many birds are larger than the females, 

 and this no doubt is the result of the advantage gained by 

 the larger and stronger males over their rivals during many 

 generations. 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 Cinclor- 

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

 ment actually twice as large as their respective females. 

 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 we shall hereafter see, the females apparently have 

 acquired 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 



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



f Sir R. Schomburgk, in " Journal of R. Qeograph. Soc.," vol. xiii, 

 1843, p. 31. 



J " Ornithological Biography," vol. i, p. 191. For pelicans and 

 snipes, see vol. iii, pp 138, 477. 



Gould, " Hand-book of Birds of Australia,** voL i, p. 395; vol. ii, 

 p. 383. 



