Why do woodpeckers peck on trees?

Woodpeckers live on grubs and insects that inhabit the crevices of a tree. The bird drills a hole in the tree and eats them. It is doing a favour to the tree for the grubs and insects are often harmful to the tree. While the woodpecker’s chisel-like beak helps drill holes in the tree, its long tongue which is sometimes twice the length of the head, help it reach far down into the tree and find its food.