o90 Townsend, Courtship in Birds. [.July 



The movements in the air that may or may 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 a dance. The ardor of courtship bears many a bird aloft, 

 and he expresses his feelings with his wings as well as with his 

 voice. One may name not only the Oven-bird and the Maryland 

 Yellow-throat, the Bobolink and the Orchard Oriole, the Semi- 

 palmated Sandpiper and the Upland Plover, the Horned Lark 

 and the Pipit, but many other birds in this category, some of 

 which, like the Song Sparrow, sing chiefly from a perch. The 

 Horned Lark mounts silently to a great height and pours forth 

 his song in long periods, sometimes out of sight in the low-lying 

 clouds. The Pipit sings as he ascends nearly vertically and, 

 arrived at the summit of his ambitions, descends quickly, still 

 singing, to the earth. 



All birds who indulge in flight song are apt to quiver their wings 

 rapidly in their ecstacy. Sometimes this motion of wings becomes 

 of primary importance and the bird flies with quivering wings 

 but voiceless, or even vibrates his wings rapidly from a perch. 

 This sometimes happens in birds that ordinarily sing at the same 

 time. I have seen it, for example, in the Song Sparrow. The 

 Pheasant quivers his wings rapidly but nearly noiselessly, then 

 emits his vocal crow to be followed by a loud clapping of the 

 wings. The Ptarmigan vibrates his wings rapidly in flight and 

 calls at the same time; the Spruce Partridge flies from a tree stub 

 to the ground with audibly vibrating wings, while the Ruffed 

 Grouse stands on a log and, by the rapid whirring of his wings, 

 emits his characteristic 'drumming.' That this drumming is 

 evolved from a flight song and that there was once a vocal part 

 of the performance, I have little doubt. These examples show 

 the stages in the evolution. 



The loud clapping together of the wings behind the back in 

 Domestic Pigeons during flight and their habit of soaring with 

 wings obliquely upwards, although common at all times, are 



