142 Zoologica: N. Y. Zoological Society. [I; 5 



known absolutely nothing of the actual cause of this phenome- 

 non ; either how it arose, why it is so persistent, or what good is 

 accomplished. 



Part II. 



The Motmot is clad in browns and greens, and is a rather 

 silent, sedentary bird. It would be thoroughly protected on its 

 perch among green foliage were it not for a constant and violent 

 jerking of the closed tail from side to side, through an arc of 45 

 to 60 degrees. This movement, accentuated by the large isolated 

 rackets, calls instant attention to the bird as one looks in its 

 direction. Its food in nature consists chiefly of insects and ber- 

 ries, although it will occasionally exhibit Shrike-like habits and 

 turn ornithophagus. 



The individual under consideration has been in my pos- 

 session since September 5th, 1908, and in general has been in 

 perfect health, moulting twice, heavily but cleanly, in September 

 of each year. When received, the rackets were broken off, but 

 the bare inch of terminal shaft showed that the tail feathers had 

 been normally stripped of web. In early October, 1908, the Mot- 

 mot began to preen the webs of its newly-grown rectrices and 

 within a week the denudation was complete. 



The upper limit of the stripped area appears always to be at 

 the tips of the second longest pair of tail feathers, so the first 

 thing I wished to discover was whether these other rectrices 

 exercised any guiding function in aiding the bird in this remark- 

 ably symmetrical trimming. 



On January 14th, 1909, I plucked out the two longest feath- 

 ers and at the same time cut straight across the second and third 

 shorter pairs of tail feathers. This took off about two and a 

 quarter inches of the second, and one and a half inches of the 

 third pair. These clipped feathers of course remained in the 

 same shortened condition until the succeeding moult, while the 

 plucked out central rectrices began growing at once. 



When full grown, they were trimmed by the bird as before 

 and careful measurements of the denuded area compared with 

 that of the previous pair of tail feathers, showed that there was 

 no variation. Without the guide of the second and third rectrice 

 tips, the trimming was as accurate as ever. 



Part III. 



Early in the fall of the present year (1909) the Motmot 

 began to moult very heavily, and became so quiet and moped so 



