° ' !92o ] Townsend, Courtship in Birds. Sol 



displays from time to time his brilliant orange-yellow tarsi and 

 feet above the water as he performs his song and dance before 

 the modest duck. Incidentally, and perhaps accidentally at first, 

 he increases the display by the spurt of water caused by the move- 

 ment of the foot. In the Merganser this spurt of water has evi- 

 dently become of primary importance and is a most conspicuous 

 feature, but it is plain that it arose from an endeavor to display 

 a colored foot. From a display of color it has become a form of 

 a dance with an added mechanical feature. All three factors of 

 courtship are so intricately mingled that it is not always possible 

 to treat of a single one alone. 



Secondly the dance, using the word in the broadest sense, is 

 frequently employed in avian courtship. In the simplest form 

 the bird spreads its tail, slightly opens its wings and puffs out 

 its feathers. This may be done rhythmically, and, with each 

 motion, the song is emitted, for song and dance are almost always 

 associated. The Bronzed Grackle illustrates this simple dance 

 and at the same time very simple song. In slightly more elab- 

 orate form the bird may also bob its head and with still more 

 elaboration swing or sway its whole body or jump up and down. 

 The Blue-headed Vireo, for example, bobs and bows in addition 

 to puffing out its yellow flanks, the Cowbird, besides puffing and 

 spreading, bobs its head and swings its whole body, the Bluebird 

 in the excitement of courtship jumps up and down on its perch 

 and the Flicker bobs and courtesies in true cake-walk fashion. 



That the dance does not necessarily mean leg movements is 

 exemplified not only by birds but by various primitive human 

 races where posturing and movements of the head, arms and 

 trunk may constitute a large part of the performance. Among 

 the ducks the movements of the head and neck are sometimes 

 very striking and bizarre. The Golden-eye, besides performing 

 with its feet in the way already described, has a remarkable head 

 and neck dance and posturing in the courtship. The drake ex- 

 tends its head and neck straight forward like a bowsprit, then 

 vertically upwards, then backwards so that the occiput rests on 

 the rump, and lastly forward to the normal position. Black 

 Ducks, Baldpates, Buffle-heads and others make short springs 

 and flights from the water; Mallards, Scaups and Pintails bob 



