BIRDB. 355 



CHAPTER XIII. 



SECONDARY SEXUAL, CHARACTERS OP BIRDS. 



Sexual difEerences— Law of battle— Special weapons— Vocal organs— In- 

 strumental music— Love-antics and dances — Decorations, permanent 

 and seasonal— Double and single annual moults— Display of orna- 

 ments by the males. 



Secondary sexual characters are more diversified and conspic- 

 uous In birds, though not perhaps entailing more Important 

 changes of structure, than in any other class of animals. I sTiall, 

 therefore, treat the subject at considerable length. Male birds 

 sometimes, though rarely possess special weapons for fighting 

 with each other. They charm the female by vocal or instrumental 

 music of the most varied kinds. They are ornamented by all 

 sorts of combs, wattles, protuberances, horns, air-distended sacks, 

 top-knots, naked shafts, plumes and lengthened feathers grace- 

 fully springing from all parts of the body. The beak and naked 

 skin about the head, and the feathers are often gorgeously colored. 

 The males sometimes pay their court by dancing, or by fantastic 

 antics performed either on the ground or in the air. In one in- 

 stance, at least, the male emits a musky odor, which we may sup- 

 pose serves to charm or excite the female; for that excellent ob- 

 server, Mr. Jlamsay,' says of the Australian muskduck (Biziura 

 lobata) that "the smell which the male emits during the summer 

 "months is confined to that sex, and in some individuals is re- 

 "tained throughout the year; I have never, even in the breeding- 

 "season, shot a female which had any smell of musk." So power- 

 ful is this odor during the pairing-season, that it can be detected 

 long before the bird can be seen.= On the whole, birds appear to 

 be the most aesthetic of all animals, excepting of course man, and 

 they have nearly the same taste for the beautiful as we have. This 

 is shown by our enjoyment of the singing of birds, and by our 

 women, both civilized and savage, decking their heads with bor- 

 rowed plumes, and using gems which are hardly more brilliantly 



' 'Ibis,' vol. iii. (new series) 1867, p. 414. 



2 Gould, 'Handbook to the Birds of Australia," 1865, vol. ii. p. 383. 



