Part Two of my Rock And Roll In Nature series: Percussion! And my favorite bird in the world.
The woodpecker! Not a rare bird, obviously, unless you’re talking about the probably-extinct Ivory-Billed Woodpecker. But the genus as a whole is a fascinating case study in animal architecture. When I think of creatures built to withstand impact, I think of the American Bison, who crash into each other with a g-force equivalent of a 40-ton wrecking ball to the forehead. But pound-for-pound, there is nothing that takes a beating like Mother Nature’s drummers, the humble woodpeckers. By all rights, they rock so hard their heads should explode.
Take your average pileated woodpecker. When pecking at a tree for insects, its head hits the wood at a force of 1200 g’s. Try to imagine running into a wall face-first at 16 mph. Now imagine doing that 20 times a second, 12,000 times a day. Now imagine wiping your brain off the inside of your skull like a loogie off a windshield.
The woodpecker manages to avoid total headsplosion by dint of a fantastically tricked-out anatomy. Everything is designed to absorb shock and send it safely past the brain: a thick, spongy skull, a set of muscles that connect the cranium and the beak.
The brain itself is tiny for a bird its size. Woodpeckers are not known for their book-smarts, but the extra negative space around their gray matter keeps them from going all Jayne Mansfield against a sugar maple. Additionally, each one of those 20 strokes per second has to be perfectly perpendicular to the tree; any torsion at all, any subtle sideways movement of the neck, and the woodpecker’s brain would literally twist off its stem. The woodpecker has evolved to hammer with the precision of an electric sewing needle.
Most fascinating to me is its tongue, one of the longest in the avian family, stretching four inches beyond the tip of the bill. Barbed on one end for drawing insects out of holes, or brush-tipped to lick up sap, it’s actually anchored near the orbital socket, exits the right nostril, splits in two, curves around the cranium, reconnects, and exits at the lower mandible, essentially becoming extra cushioning for its head. In other words, the woodpecker is licking its own skull.
That’s fine for its brain, but wouldn’t an impact force of 1,200 times the force of gravity make your eyes pop out of their sockets? Evolution has that covered, too. Birds have a transparent “third eyelid” called a nictating membrane that function like aviator goggles or, for kingfishers and other diving birds, diving goggles. In woodpeckers, the nictating membranes serve as carpenter’s goggles, raised a millisecond before each strike to keep flying wooden debris out while keeping the eyeballs in.
I’ve always thought of woodpeckers as tree surgeons: precise, careful, scientific. And so they are. But they’ve also got anatomies that are built for hard rocking, and when it comes to drum solos, they’re hard to beat.