Why does a woodpecker peck? The woodpecker pecks into tree trunks or limbs for several reasons. First, it is a mating call. Second, the pecking creates a hole for a nest, with the wood chips it leaves forming a cushion for its eggs. But mostly it is done in search of food. Once the hole is made, the woodpecker’s long tongue shoots into the hole and spears insects on a barb at the tip of its tongue.