Woodpeckers have a special bone that acts like a seat-belt for its skull. It's called the hyoid bone, and it wraps all the way around a woodpecker's skull. Every time the bird pecks, the hyoid acts like a seat-belt for the bird's skull and the delicate brain it protects.
Using the pressure law (P1 x V1)/ T1 = (P2 x V2)/ T2 where P1= the initial pressure V1= initial volume T1= initial temperature and P2= the final pressure V2= the final volume T2 = the final temperature and temperature is always in kelvin