COURTSHIP IN BIRDS 269 



raised and waved again and so on over and over 

 again. Owing to the great volume of sound 

 from the ledges it is impossible to distinguish any 

 individual performer, and I was unable to tell at 

 what point in the dance and to what extent the 

 song was important. The sound is like that of 

 a thousand rattling looms in a great factor} , a 

 rough, vibrating, pulsing sound — car-ra^ car-ra, 

 car-ra. 



The movements in the air that may or ma}- not 

 be accompanied with song may be classed in this 

 division of the dance. The bobolink, rising in 

 irregular circles, or progressing in a horizontal 

 plane on rapidly vibrated down-curved wings, is 

 expressing his amorous feelings by dance as well 

 as by song. His flight often concludes by a 

 rapid descent with wings pointing obliquely up- 

 ward, forming a display by posture and motion — 

 in themselves forms of dance. The ardor of 

 courtship bears many a bird aloft, and he ex- 

 presses his feelings with his wings as well as with 

 his voice. One may name not only the oven-binl 

 and the Maryland yellow-throat, the bobolink 

 and the orchard oriole, the semipalmated sand- 



