PLANT-EATING BIRDS, REPTILES, AMPHIBIANS, FISHES 189 



not have noticed its chief peculiarity, which consists in the power 

 of freely moving the upper half as well as the lower, an obviously 

 useful arrangement. Even more useful is the power of holding 

 the food in one of the climbing feet, while the bird stands upon 

 the other. Parrots are social in habit as a general rule, and feed 

 in flocks or companies. An example of this is the nocturnal 

 flightless Owl - Parrot (Stringops habroptilus) of New Zealand, 

 which comes out of its 

 hiding-place at night to 

 feed upon the ground, 

 making with its companions 

 broad tracks upon the 

 vegetation a foot or more 

 wide. Some, members of 

 the group dig for their 

 food, of which a good in- 

 stance is the Slight-billed 

 Parraquet {Hemicognathus 

 leptorhynchus) of Chili, the 

 long and slender upper 

 mandible of which is well 

 suited for attacking grass- 

 roots, as well as for extract- 

 ing grain from the husk. 

 But the most remarkable 

 case of specialization is 

 that of the Great Black 

 Cockatoo {Microglossus aterrimus) (fig. 431) of North Aus- 

 tralia and the New Guinea islands, a bird of the size of 

 a large crow, with an enormous beak, but a small worm -like 

 tongue with a horny tip. Semon (in In the Australian Bush) 

 alludes to this species as "one of the largest parrots existing, 

 and furnished with a bigger and stronger beak than any other. 

 This beak enables the bird to open even the strong fruits of the 

 kanary-tree. It serves it as saw and borer, and in the place of 

 cutting nippers, while its tongue, which is horny at the end, is 

 useful in removing the kernels or the flesh from the tapped or 

 broken-up fruit." The use of the beak was worked out in detail 

 by Wallace, who describes it (in The Malay Archipelago) as fol- 

 lows: — "The great black cockatoo frequents the lower parts of 



Fig. 431. — Great Black Cockatoo {Microglossus aierrinius) 



