Beak (or Bill)

A bony extension of a bird’s skull, the beak (also called a bill or rostrum) includes an upper and lower jaw covered by a horny, proteinaceous sheath. 

The beak is used for eating and for grooming, manipulating objects, killing prey, probing for food, courtship and feeding young. The term may also refer to a similar mouthpart in some other kinds of organisms.

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