By Wendy Langhans
Who among us hasn't hit their head? Whether it's a cabinet door left open or a slippery banana peel, we all know what it feels like. IT HURTS!
But woodpeckers are constantly banging their heads against trees. We often hear Acorn woodpeckers  and Nuttall's woodpeckers  pounding on trees to get at the tasty insects lying beneath the bark.
And in the fall, Acorn woodpeckers also drill holes in trees or fence posts, where they store acorns  for consumption later in the winter.
Acorn woodpeckers store acorns in a "Granary Tree"
Each time a woodpecker bangs its beak into a tree - at a speed of 12 mph and a rate of 20-25 times per second - its "head absorbs 1,300 pounds of force ." We know that humans often suffer brain damage from head trauma. So why don't woodpeckers get brain damage?
In sorting through the literature, I found five reasons why.
1) The bones in their skull are "spongy" and absorb some of the shock before it reaches the brain.
The next two reasons can be explained by this equation from High School physics: Stress = force/area or (mass x deceleration)/area.
2) Their brains are small, with a large surface/weight ratio. This means that, relatively speaking, the force of impact is spread out over a larger area.
3) The duration of deceleration is small - about .5 millisecond.
The fourth reason is we call the "contre coup" affect, when the skull "bounces back" after impact, causing a secondary hit by the back of the brain against the back of the skull.
4) Woodpeckers have less cerebral-spinal fluid in their brains, so there is less brain movement inside their skull. For a more thorough explanation of this effect, go here  and look on page 9.
And the last reason has to do with the rotational force applied to the brain, a shear force that can tear brain neurons apart:
5) Many, but not all woodpeckers, peck in a straight line . This minimizes the rotational force.
So, the next time you have a frustrating day and feel the urge to hit your head against the wall, just remember that your brain is larger and more fragile than a woodpecker's. But if you decided to do it anyway, I recommend that you DON'T take a running start, WEAR a helmet and HIT the wall straight on.
Upcoming Outdoor Events:
Saturday, August 22nd, and every Wednesday, 8:00 AM. Trail Maintenance Volunteers at Towsley Canyon .
Come join our trail maintenance volunteers for camaraderie and a heart-thumping workout. For more information contact Steve Ioerger  at 661-291-1565.
Saturday, August 22, 2009. Acorns, Sea and Sage: Chumash Native Americans. Ranch house at William S. Hart Museum.
Discover how the Chumash used their natural resources to survive hundreds of years ago. You even have a chance to grind your own acorns! Activities geared for 3-10 year olds, but all ages welcome. Adults must accompany child. For more information, call 661-254-4584 or visit www.hartmuseum.org .
Friday, September 4, 7:30-9:30 PM. Full Moon Hike.
Come see Towsley Canyon  in a different light. We meet at the front gate. Families welcome.
You can listen to stories like this every Friday morning at 7:10 a.m. on "The Hike Report", brought to you by your hometown radio station KHTS (AM1220) and by the Mountains Recreation and Conservation Authority.