Woodpeckers are best known as the family that chisel into tree trunks with their beaks. Most species eat insects that they prise out of wood with their beaks and tongue, but the sapsucker consumes tree sap. Wrynecks are also in this group and spend most of their time on the ground feeding on ants. The woodpeckers, piculets, wrynecks, and sapsuckers are a family, Picidae, of near-passerine birds. Members of this family are found worldwide, except for Australia, New Zealand, Madagascar, and the extreme polar regions. Most species live in forests or woodland habitats, although a few species are known to live in treeless areas, such as rocky hillsides and deserts.
The Picidae are just one of the eight living families in the order Piciformes. Members of the order Piciformes, such as the jacamars, puffbirds, barbets, toucans, and honeyguides, have traditionally been thought to be very closely related to the woodpeckers, piculets, wrynecks, and sapsuckers. More recently, DNA sequence analyses have confirmed this view.
There are about 200 species and about 30 genera in this family. Many species are threatened or endangered due to loss of habitat or habitat fragmentation. Two species of woodpeckers, the Ivory-billed Woodpecker and the Imperial Woodpecker, have been considered extinct for about 30 years (there has been some controversy recently whether these species still exist).