Birds need to use the beak a good deal, because in most cases it grows like our finger-nails. If they did not keep it worn off, it would grow so long as to trouble them. Sometimes when a bird lives in a cage and does not use his bill, it grows so long that he can hardly pick up his food.
The woodcock's long beak is sensitive, so that he can feel the worms, deep in the mud where they live. Many waders and swimmers have beaks soft like leather.
You can tell by the shape of the beak how a bird lives, and what he eats. The strong, hooked beak of a hawk shows that he catches live animals to eat ([Fig 4]). The long, narrow, sharp bill of a heron shows that he spears his prey, often under water.
The sharp-pointed bill of a warbler is to pick tiny insects and eggs out of blossoms, and from under leaves. The sharp-edged bill of a sparrow (Fig. 5) is to break open the hard shells of seeds.
