Water-Birds Woodpecker. 109 



it ; both perfectly fitted for their work and harmo- 

 nizing with each other. 



In water-birds we find the web foot for swimming, 

 and bills fitted for their mode of life. The wide- 

 billed ducks have strainers on the sides of the 

 mouth, because they gather their food from the 

 mud and water. The narrow-billed sheldrake has 

 the sharp saw-teeth which his instinct teaches him 

 to use in holding his fishy prey. In those birds 

 whose habits confine them mostly to the water, like 

 the grebq >r loon, the leg is thin as a knife, that it 

 may cut the water with as little resistance as pos- 

 sible, and each tO i> an <>ar of most exquisite con- 

 struction. The feathers of such birds are water- 

 proof. The waders, like the herons and snipes, are 

 provided with long legs and long necks to harmo- 

 nize with them in pursuit of prey and in flying. The 

 leathers on the legs of these waders do not grow 

 clown to the middle joint as in other birds, but keep 

 out of the way of the water like sleeves well rolled 

 up. So perfectly are the bills of all birds adapted 

 to their instincts, that from the bill alone the habits 

 of a bird one had never seen could be judged of 

 with great accuracy. The woodpecker is the best 

 and most familiar example of this special and har- 

 monizing structure. Its sharp bill is for piercing 

 wood ; its foot, with two toes in opposite directions, 

 is just fitted for clinging to the limbs on either side, 

 or upon the bark. Its tail-feathers are stiffened 

 and sharpened at the points to act as supports ; its 

 tongue is barbed like a steel spear. What a perfect 



