Because the head of a woodpecker is a perfect hammer. The whole anatomy of birds is designed in such a way that the woodpecker can knock with all its force on all kinds of trees without harming it. Any other bird would die, but our birds do not care! The whole complex - the system of muscles, cartilage and spongy bones absorb shocks, although it absorbs shocks, it also gets very hot. Therefore, birds are regularly forced to take breaks and cool their wild heads SaveInsta.App VK.