Chap. XV. DEVELOPMENT OF SPUES. 163 



struct a different sort of nest, not liable to be injured 

 by their spurs, from that made by their nearest allies, 

 so that there has been no need for the removal of 

 their spurs ? Or are we to suppose that these fe- 

 males especially require spurs for their defence ? It 

 is a more probable conclusion that both the presence 

 and absence of spurs in the females result from dif- 

 ferent laws of inheritance having prevailed, independ- 

 ently of natural selection. With the many females 

 in which spurs appear as rudiments, we may conclude 

 that some few of the successive variations, through 

 which they were developed in the males, occurred 

 very early in life, and were as a consequence trans- 

 ferred to the females. In the other and much rarer 

 cases, in which the females possess fully developed 

 spurs, we may conclude that all the successive varia- 

 tions were transferred to them ; and that they gra- 

 dually acquired the inherited habit of not disturbing 

 their nests. 



The vocal organs and the variously-modified feathers 

 for producing sound, as well as the proper instincts 

 for using them, often differ in the two sexes, but are 

 sometimes the same in both. Can such differences be 

 accounted for by the males having acquired these organs 

 and instincts, whilst the females have been saved from 

 inheriting them, on account of the danger to which 

 they would have been exposed by attracting the at- 

 tention of birds or beasts of prey ? This does not 

 seem to me probable, when we think of the multitude 

 of birds which with impunity gladden the country with 

 their voices during the spring.^ It is a safer conclu- 



" Daines Barrington, however, thought it probable (' Phil. Trausact.' 

 1773, p. 164) that tew female birds sing, because the talent would have 



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