450 



XEPT1LES AND BIRDS. 



ascension by extending their toes, supplied with bent claws, upon the 

 trunk of a tree, and maintain themselves hanging there then move 

 themselves a little farther by a sudden and jerked skip, and so on. 

 These movements are facilitated by the disposition of the tail, formed 



Fig. 176. Ivory-billed Woodpeckers 



of straight resistant feathers, slightly worn away at their extremities, 

 which, pressed against a tree, serve as a support 'to the bird. Thanks 

 to this organisation, Woodpeckers traverse trees in every direction 

 downwards, upwards, or horizontally. Woodpeckers are of a timid 

 and restless disposition; they live alone in the mi^st or on the 



