26 FORM AND HABIT: THE TAIL, 
This singular habit is practiced by numerous species » 
of Motmots, ranging from Mexico to Brazil. It is there- 
fore of undoubted age, and we can only speculate upon 
its use and origin. Young birds from the nest, reared 
4 
f if/ 
} \y y/ My fq \ 
iN AN ; My \ im (/ 
Fre. 11.—Central tail-feathers of Motmot (Momotus subrufescens), showing 
newly grown feathers (at the left) and results of self-inflicted mutilation. 
in confinement where they were isolated from others of 
their kind, trimmed their tail-feathers soon after they 
were grown.* 
The habit, therefore, is inherited, but the mutilation, 
although it has doubtless been practiced for countless 
generations, has not become inherent, unless we consider 
the constriction in the vane of the feather at the place 
where it is to be trimmed an indication of inheritance. 
The Motmot gesticulates with its tail in a remarkable 
manner, swinging it from side to side, so that it suggests 
the pendulum of a clock, or sweeping it about in circles 
with a movement which reminds one of a bandmaster 
flourishing his baton. We shall find in other species, 
also, that the tail, more than any other organ, is used to 
express emotion. Recall its twitching and wagging ; how 
it is nervously spread or “jetted,” showing the white 
* See Cherrie, The Auk (New York city), vol. ix, 1892, p. 322. 
