146 BULLETIN 162, UNITED STATES NATIONAL MUSEUM 



a rotating motion and commenced a series of short hisses, each one 

 sounding like drawing the palm of one's hand rapidly backward, 

 forward, and backward again over the sleeve or the trouser leg. He 

 shook his head more and more rapidly, the hisses corresponding, and 

 finally with a quick little run forward and a prolonged hiss, he 

 struck a pose and held it for several seconds. In this pose the tail 

 was swung over more to one side, the rump feathers on the offside 

 lifted, and the extended head and ruff turned toward the female. 

 The male continued this strutting and posing, usually on the log 

 but sometimes in front of the crate, until 5.30, when he attempted 

 to mate with the female reaching his head far down through the 

 wire and apparently seizing hold of her, for he pulled out at least 

 one feather. He went through all the motions of actual mating 

 though the wire separated them by several inches. He then pro- 

 ceeded down the log to his accustomed place and drummed. This 

 seems rather significant as indicating that the drum is probably a 

 challenge to other males even more than an announcement of his 

 presence to the female. 



"Audubon states that ' the female, which never drums, flies 

 directly to the place where the male is thus engaged,' but so far as 

 I know, no one has ever seen a female grouse come to the male on or 

 near his drumming log, although a great many hours have been spent 

 by different observers watching the drumming bird. I think we are 

 justified in concluding that while she may do so occasionally, she does 

 not do so with any regularity and that the male must find her some- 

 time during the day when he is not drumming. The drumming, 

 therefore, resolves itself primarily into a challenge to other males 

 to keep out of the drummer's territory. 



" Let us next analyze how the sound is produced. The ordinary 

 drum, such as the one filmed, requires almost exactly 8 seconds from 

 the first wing beat until the last. With the motion-picture camera 

 taking 16 pictures per second, the performance is registered on 123 

 frames. The first one or two wing beats are almost silent and are 

 given while the bird is in a nearly normal horizontal position, the 

 wings striking downward and inward. The bird's tail is being 

 lowered against the log during this preliminary beat or beats. Then 

 abruptly he stands erect with his tail against the log, wings drooping 

 at his sides and appears to throw his ' shoulders ' back. This might 

 give the impression that the wings were struck behind the back, 

 because the forward stroke of the wing follows so instantaneously 

 that the eye scarcely perceives it, and it is given with such force and 

 the wings come back to the normal position so quickly that the 

 entire action registers on only one frame of the motion-picture film 

 having an exposure of approximately one-fiftieth of a second. Be- 



