NATURAL HISTORY. 261 



&quot; O who would e er have thought that time could have decay d 

 Those trees whose bodies seemed by their so massy weight 

 To press the solid earth, and with their wondrous height 

 To climb into the clouds.&quot; DRAYTOX. 



and in those climates to localities where the vegetation is so 

 uxuriant that the forests are impenetrable by man. 



It is the office of the parrot tribes to keep in check this excessive 

 vegetation, and to prune the trees which they inhabit. A parrot in 

 the woods has harder labour to perform than almost any other bird 

 which lives upon vegetable matter. And it is remarkable that 

 they gnaw and chip wood, not for the purposes of appetite ; but 

 because this occupation affords them a great degree of pleasure. 



Through this biting propensity, they contribute to the removal 

 of decayed trees, by enlarging the holes in their trunks, and 

 exposing the woody fibre to the action of the rain 

 and atmosphere. 



810. What important advantage does the parrot derive from 

 the moveability of its upper mandible? 



The upper mandible being moveable, and not, as in other birds, 

 united to the cranium, prevents pressure or concussion being 

 communicated to the brain, while the bird performs the arduous 

 gnawing task assigned to it. 



811. Why are paraquettes so called? 



The term may be considered as a diminutive of parrot, and is 

 used to distinguish the smaller birds of the parrot tribes. 



812. Why are paraquettes abundant in America. 



In the great western valley of the United States, there grows 

 a wild plant, of the composite order, known as the cocldt^burr. 

 The seeds of these plants are the favourite food of paraquettes. 

 But for the check afforded by these birds to the diffusion of this 

 plant, it would probably spread itself over every piece of ground 

 which man has cleared of timber, or reclaimed from being 

 a swamp. 



813. Why does the parrot construct no nest? 



The soft dust accumulated at the bottom of the trunks of 



