The yellow-bellied sapsucker averages eight to nine inches in length (tail tip to bill tip in preserved specimen). It has black and white bars on its back and tail feathers. There is a white patch on each wing and a red forehead patch. The male also has a red throat patch, while the female has a white throat patch. The immature bird is more brown than the adult and lacks the red or white throat patch but is still barred on the back and tail and has white wing patches. As a woodpecker, the sapsucker has zygodactylous feet (two toes face forward and two backward). Its strong, pointed bill allows this bird to peck holes in wood. The long tongue is used for extracting food from the wood. The tail is rigid, helping the bird cling to the side of trees.
The yellow-bellied sapsucker is a common migrant, common winter resident decreasing northward and a rare summer resident in northern Illinois. It lives in deciduous and coniferous woodlands. This woodpecker migrates at night. Spring migrants begin arriving in late March. The yellow-bellied sapsucker nests in the northern one-half of Illinois. Eggs are produced from April through June. The nest is built in a hole excavated in a tree or stump. The birds may nest in the same cavity for several years. Both the male and female build the nest that requires about one week to construct. Four to seven, white eggs are deposited by the female. The male and female alternate incubation duties over the 12- to 13-day incubation period. Fall migrants begin arriving in September. Those sapsuckers that winter in Illinois tend to be in residential areas, parks and cemeteries in the northern part of the state and in bottomland forests in the southern part of the state. Others may winter as far south as Panama. The yellow-bellied sapsucker drills holes in rows on trees. It feeds on insects, fruits and the sap and cambium of trees. This bird makes a squealing call and has a distinctive drumming pattern of several rapid thumps followed by several slower ones.