THE WOODPECKER'S TOOLS: HIS TAIL 97 



that cannot be dislodged except by a forward 

 motion of the bird or by hfting the tail. Com- 

 pared with this, the spiny points on the flicker's 

 tail were a poor invention. This device, which 

 takes hold like a wool card, or a wire hair-brush, 



Under side of middle tail feather of Ivory-billed Woodpecker. 



cannot slip from place. We begin to see, too, the 

 use of that weak and flexible tip ; it is to press 

 down upon the tree-trunk a flat surface suffi- 

 ciently large to hold hundreds of these little 

 spiny points against the bark. The ivory-bill 

 braces against this with the stiff upper part of 

 the shaft and has a support that will not slip. 

 The upper part of the shaft acts like a spring 

 also, and adds tremendous force to the blow 

 of the bill. Watch a hairy woodpecker when 

 hard at work and see how his legs and tail 

 form a triangular base by bracing against each 

 other, and how his blow is delivered, not with 

 the head alone, but with the whole body, swing- 

 ing from the hips, the apex of the triangle on 

 which he rests. He swings like a man wielding 

 a sledge hammer, and to the strength of his neck 

 adds the weight of his body, the spring of his 



