Why don't woodpeckers suffer from headaches even though they are banging their heads against the wall most of the time?
That's a difficult question to answer, said Walter Koenig, an ornithologist at Cornell University. If pecking leads to injury and pain, the species would have perished by now since a hurt bird is likely to succumb to its predators, he added.
Over 300 species of woodpeckers in the world peck wood for a number of reasons. It may be to drill holes for food storage, dig for sap or insects, or simply unearth nest cavities. The birds normally target trees drained by fungal infection since they are easy to crack, said Jerome Jackson, an ecologist at Florida Gulf Coast University.
Woodpeckers do not give a direct hit, but gradual blows, which are not so hard on the creature. Some practice drumming on resonant surfaces, such as a hollow tree. This super-fast pecking action creates a loud noise but avoids punishing impacts besides defending the territory and attracting mates. Acorn woodpeckers found in North and Central America use another strategy: They create individual holes and store food for the dry season, said Jackson.
The weight of a woodpecker's brain is just around 0.07 ounce. The risk of brain injury is thus greatly reduced because of its tiny size, according to Lorna Gibson, a professor at MIT. Another factor that safeguards the bird from noggins is the restricted time of contact between the bird's bill and the tree. It's only 0.5 to 1 millisecond. A typical human head injury occurs between 3 and 15 milliseconds.
Also, the outer part of the woodpecker's skull is composed of dense bones. while the inner part is made up of porous bone, said Gibson. The force at which a woodpecker pecks wood is distributed in the skull area and the back, which keeps the pressure away from the brain, according to Richard Prum, an ornithologist at Yale University.