Members of the family Picidae have strong bills
for drilling and drumming on trees and long sticky tongues for extracting food. Woodpecker bills are typically longer, sharper and stronger than the bills of piculets and wrynecks; however, their morphology
is very similar. The bill's chisel-like tip is kept sharp by the pecking action in birds that regularly use it on wood. Species of woodpecker and flicker that use their bills in soil or for probing as opposed to regular hammering tend to have longer and more decurved bills. Due to their smaller bill size, many piculets and wrynecks will forage in decaying wood more often than woodpeckers. The long sticky tongues, which possess bristles
, aid these birds in grabbing and extracting insects deep within a hole of a tree.
From Wikipedia, the free encyclopedia http://en.wikipedia.org/wiki/Woodpecker