The woodpecker is a member of the Picidae family. Picidae is a group of birds close to the bird shape, including the small elephant shaped characters, wolf WR and woodpecker. With the exception of Australia, New Guinea, New Zealand, Madagascar and polar regions, the family has members all over the world. Most species live in forest or woodland habitats, although a few live in treeless areas, such as rocky hillsides and deserts, while the Gila woodpecker specializes in cactus development.

Members of the family are mainly known for their unique behavior. Most of them forage for insects on tree trunks and branches, and often communicate with their beaks and drums, producing reverberating sound that can be heard at a certain distance. Some kinds of food feed on fruits, eggs, small animals and SAP. Most of them live in the holes on the trunk, and the abandoned holes are also important for other nest birds. When they make holes in buildings or feed on fruit crops, they sometimes conflict with human beings, but they play a beneficial role by eliminating pests on trees.

Picidae is one of nine living families in the order of Piciformes, the others are tropical toucans (including three families), toucans, tropical toucans and honey guides in Pici evolutionary branch, jacaars and puffins in galbuli evolutionary branch. DNA sequencing confirmed the sister relationship between the two groups. Picidae family includes about 240 species in 35 genera. Due to habitat loss or habitat fragmentation, nearly 20 species are threatened with extinction, one of which is the Bermuda flash extinction, the other may be extinction.

A woodpecker's length never exceeds 7 cm (2.8 in.), a small skin pecker weighing 7 g (0.25 oz.) and a large woodpecker over 50 cm (20 in.) in length. The most surviving species are the great plank woodpeckers, which weigh 360 – 563 grams (12.7 – 19.9 ounces), but the extinct imperial woodpeckers and ivory billed woodpeckers may both be larger.

The feather of woodpecker changes from monotonous to obvious. Many species are based on olive and brown colors, while others are light, indicating a need for camouflage. Others stand out in black, white and red, many of which are decorated with crowns or clusters of feathers. Woodpeckers tend to be bisexual, but the differences between the sexes are usually small. Williamson's woodpecker is an exception to the orange backed Woodpecker. They are very different. In addition to the insect, the feather coat should be completely feathered once a year, and some feathers should be changed before reproduction.

Woodpeckers, pinkies, and sunken boats all have characteristic 12 toed feet, made up of four toes, the first (toenail) and fourth toes facing back, and the second and third toes facing forward. This arrangement of feet is very useful for grasping the limbs and trunk of trees. Members of the family can walk vertically on the tree trunk, which is very beneficial for activities such as foraging or nest digging. In addition to their powerful claws and feet, woodpeckers have short, strong legs. This is a typical bird that forages regularly on its trunk. Except for the black backed Woodpecker and the American and Eurasian three toed woodpecker, each foot has only three toes. With the exception of woodpeckers and wrecks, all woodpeckers' tails harden, and when the bird perches on a vertical surface, its tail and feet support it together.