Chap. X I i I . Vocal Music. 3 7 ] 



though they never sing, and do not naturally modulate their 

 voices to any great extent. Hunter asserts 38 that with the true 

 songsters the muscles of the larynx are stronger in the males 

 than in the females ; but with this slight exception there is no 

 difference in the vocal organs of the two sexes, although the 

 males of most species sing so much better and more continuously 

 than the females. 



It is remarkable that only small birds properly sing. The 

 Australian genus Menura, however, must be excepted ; for the 

 Menura Alhrti, which is about the size of a half-grown turkey, 

 not only mocks other birds, but " its own whistle is exceedingly 

 " beautiful and varied." The males congregate and form " cor- 

 rohorying places," where they sing, raising and spreading their 

 tails like peacocks, and drooping their wings. 39 It is also remark- 

 able that birds which sing well are rarely decorated with brilliant 

 colours or other ornaments. Of our British birds, excepting 

 the bullfinch and goldfinch, the best songsters are plain-coloured. 

 The kingfisher, bee-eater, roller, hoopoe, woodpeckers, &c, utter 

 harsh cries ; and the brilliant birds of the tropics are hardly ever 

 songsters. 40 Hence bright colours and the power of song seem 

 to replace each other. We can perceive that if the plumage did 

 not vary in brightness, or if bright colours were dangerous to the 

 species, other means would be employed to charm the females ; 

 and melody of voice offers one such means. 



In some birds the vocal organs differ greatly in the two sexes. 

 In the Tetrao cupido (fig. 39) the male has two bare, orange- 

 coloured sacks, one on each side of the neck; and these are 

 largely inflated when the male, during the breeding-season, 

 makes his curious hollow sound, audible at a great distance. 

 Audubon proved that the sound was intimately connected with 

 this apparatus (which reminds us of the air-sacks on each side ol 

 the mouth of certain male frogs), for he found that the sound was 

 much diminished when one of the sacks of a tame bird was 

 pricked, and when both were pricked it was altogether stopped. 

 The female has " a somewhat similar, though smaller naked space 

 " of skin on the neck ; but this is not capable of inflation." 41 The 



38 As stated bv Barrington in in Canada,* by Major W. Ross King, 

 ' Philosoph. Transact.' 1773, p. 262. 1866, pp. 144-146. Mr. T. W., 



39 Gould, ' Handbook to the Birds Wood gives in the ' Student ' 

 of Australia,' vol. i. 1865, pp. 308- (April, 1870, p. 116) an excellent 

 310. See also Mr. T. W. Wood in account of the attitude and habits 

 the 'Student,' Auril 1870, p. 125. of this bird during its courtship. 



40 See remarks to this effect in He states that the ear-tufts or neck- 

 Grould's ' Introduction to the Trochi- plumes are erected, so that they 

 ldte,' 1861, p. 22. meet over the crown of the head. 



41 ' The Sportsman and Naturalist See his drawing, fig. 39. 



