WOODPECKERS 167 



so as to fit them for their pecuhar mode of life. The 

 most obvious of these changes are in the shape of the 

 beak, the tail, and the feet. Their food consists of 

 insects and grubs which they find concealed in the 

 bark of trees. The beak is wedge-shaped and sharply 

 pointed, and has a horny sheath of unusual hardness, 

 enabling the bird to peck away the bark in search of 

 its prey, and also to dig the holes in which it makes 

 its nest. The toes are placed two in front and two 

 behind, and are furnished with long claws, which serve 

 the purpose of grappling-irons. Finally, the tail- 

 feathers are of a curious spiny character, and these 

 serve as supports when the bird, having firmly fixed 

 itself by its claws, begins its work of excavation. The 

 Woodpeckers are essentially tree-dwellers, and after a 

 peculiar fashion, for they spend most of their lives, 

 not in perching on the boughs, but in climbing up and 

 down the trunk. The spiny tail-feathers are devel- 

 oped in proportion to the amount of hammering which 

 must be performed to gain a livelihood. They afford, 

 in short, a very effective leverage during the time that 

 the beak is being used as a "pick." 



But the peculiarities of the Woodpeckers do not 

 end with these external characters. The tongue, for 

 example, is of enormous length, and its roots, or sup- 

 ports, are excessively developed, so that they curve 

 round and over the skull, to be finally stowed away in a 

 channel above the beak. This tongue is used as a trap 

 for the capture of ants and other insects. Thickly 

 covered with a sticky saliva, which has been compared 

 to bird-lime, this wonderful and worm-like organ is 

 suddenly thrust out amid swarms of ants, which are 



