Woodpecker beaks must be pretty sharp to pierce wood. I would imagine that they must lose their sharpness due to wear and tear. Am I right? How do they keep their beaks sharp?
Yeah. And another thing I read in a magazine years ago was some guy doing studies on how they keep from scrambling their brains when they pound their heads on wood hard enough to dig a hole in the wood.
Straightdope to the rescue as to why they don’t bash their brains out 
And as an aside, check out their tongues :eek:
When I was at a park once walking my dogs I saw a woodpecker on top of a light pole that was used to light a baseball field just hammering away at the metal light fixture.
That has to be one of the funniest things I’ve ever seen.
Woodpeckers drum on anything that produces a “good” sound to advertise their territory.
Really? I thought they only hammered to extract grubs from under the tree bark. Is there a territorial thing going on too?
Yes. Woodpeckers deliberately make loud drumming sounds by pounding on trees, posts, aluminum siding, or whatever to advertise their territory.
As for the OP, a bird’s horny beak grows, just like fingernails, so that the parts that are subject to wear get replaced.
Oddly enough, I asked this question BEFORE finding out that they just discovered a rare breed of woodpecker long believed extinct. Quite an improbable series of events!
The beak of a bird enjoys rejuvenation on a continual basis. I see this with my parrot, and also note a similar phenomenon with cat nails, as the outer sheath is shed.