COURTSHIP IN BIRDS 273 



secondary or incidental to the production of son^ 

 to be described later. The erection of the neck- 

 wings which ordinarily help cover the deflated 

 neck-sacks, the spreading and erection of the tail, 

 the vibration of the down-stretched wings, the 

 pirouetting and turning of the body and the 

 rapid stamping of the feet in this species are all 

 forms of the dance. 



Lastly, in this brief review and rough classi- 

 fication of the courtship actions of birds, the song 

 is to be considered. By song I do not mean 

 necessarily a melody or musical strain pleasing 

 to human ears — although many of these pro- 

 duced by the higher species of birds are extremely 

 pleasing — but any sound which is customarily 

 connected with courtship. Courtship song, as 

 thus understood, may be either vocal or instru- 

 mental. The rattling of the stiff tail feathers 

 of the peacock and the rolling drum made by 

 the wings of the ruffed grouse fall into the instru- 

 mental category. The rapid stamping of the 

 feet by the heath hen produces a ratta-tat-tat 

 like that made on a kettle drum. The tooting 

 sound, similar to that made by blowing across 



