48 SEXUAL SELECTION: BIRDS. ^F^ht II. 



yield to the victorious males. It is more probable that 

 the females are excited, either before or after the conflict, 

 by certain males, and thus unconsciously prefer them. In 

 the case of Tetrao umbellus, a good observer 23 goes so far 

 as to believe that the battles of the males " are all a sham, 

 performed to show themselves to the greatest advantage 

 before the admiring females who assemble around ; for I 

 have never been able to find a maimed hero, and seldom 

 more than a broken feather." I shall have to recur to . 

 this subject, but I may here add that with the Tetrao 

 cupido of the United States, about a score of males assem- 

 ble at a particular spot, and strutting about make tha 

 whole air resound with their extraordinary noises. At 

 the first answer from a female, the males begin to fight 

 furiously, and the weaker give way ; but then, accprding 

 to Audubon, both the victors and vanquished search for 

 the female, so that the females must either then exert a 

 choice, or the battle must be renewed. So, again, with 

 one of the Field-starlings of the United States (Sturnella 

 ludoviciana) the males engage in fierce conflicts, " but at 

 the sight of a female they all fly after her as if mad. 



75 24 



Vocal and Instrumental 3fusic. — With birds the voice 

 serves to express various emotions, such as distress, fear, 

 anger, triumph, or mere happiness. It is apparently 

 sometimes used to excite terror, as with the hissing noise 

 made by ilome nestling birds. Audubon 25 relates that a 

 night-heron (Ardea nycticorax, Linn.), which he kept 

 tame, used to hide itself when a cat approached, and then 

 " suddenly start up uttering one of the most frightful cries, 

 apparently enjoying the cat's alarm and flight." The 



23 'Land and Water,' July 25, 1868, p. 14. 



24 Audubon's ' Ornitholog. Biography ; ' on Tetrao cupido, vol. ii. p. 

 492 ; on the Sturnus, vol. ii. p. 219. 



25 ' Ornithological Biography,' vol. v. p. G01. 



