154 THE BIOLOGY OF THE SEASONS 



is a tendency to transfer our analytic scientific way of 

 looking at things to birds and beasts that probably leads 

 us into many mistakes. It is extremely improbable that 

 any female bird accepts a suitor on account of his musical 

 or quasi-musical talents. 



Another view, which has the great name of Wallace 

 behind it, interprets the love-call as a means of recognition 

 between related forms, and as a signal which brings sparsely 

 scattered birds together. It is highly probable that 

 singing sometimes has these secondary advantages, but the 

 frequent elaborateness of the song seems to require some 

 other interpretation. 



Wallace also suggested that singing was a pleasure, 

 and probably helped as a safety-valve for superfluous 

 nervous energy, just as a dance does. Herbert Spencer 

 elaborated the same view that the song is not in any sense 

 a kind of courtship, but simply expressed an overflow of 

 nervous energy. The dog wags its tail when pleasurably 

 excited, the bird works the muscles of its syrinx. This 

 theory is too simple to be the whole truth, but it lays 

 emphasis on a very important fact the close association 

 between emotion and muscular movements. 



There seems much to be said for the thesis well worked 

 out by Professor Groos in his Play of Animals that 

 instinctive coyness has been evolved as a feminine character- 

 istic of great importance as " the most efficient means of 

 preventing the too early and too frequent yielding to sexual 

 impulse. A high degree of excitement is necessary for both, 

 but the female has an instinctive impulse to prevent the 

 male's approach, which can only be overcome by persistent 

 pursuit and the exercise of all his arts." Song is one of 

 these arts by which the male stimulates his desired mate to 

 passion. 



Nor is the female's response of less importance in 



