Beaks are used for eating, defense, feeding young, gathering nesting materials, building nests, preening, scratching, courting and attacking. The shape and size of each species' bill is specific for the type of food it gathers. Cardinals have heavy thick bills used to crack seeds. Meat-eaters, like the eagle, have a sharp, hooked bill to tear flesh. Humming-birds have thin bills to sip nectar.
Birds use their tongues for a variety of jobs also.
Not only are tongues used to drink, but also to hold, pierce and tear food. Small stones and grit in the gizzard grind the food. The gizzard is made of strong muscles. In the wood duck those muscles can break down a whole acorn. Birds have a high metabolic rate and must eat often to survive.