Acorn Woodpecker (Melanerpes formicivorus)

The Acorn Woodpecker (Melanerpes formicivorus) is a relatively common bird species found in habitats extending from Oregon, California and Western Mexico, right through to the highlands of Central America as well as the Colombian Andes. Described as having a clown-face, the Acorn Woodpecker is a very social creature, with groups living together in a complex social system. A fascinating bird, the Acorn Woodpecker is worth looking out for.

Acorn Woodpecker’s can be quickly identified by the following distinctive features: a white eye ringed by black; black around the classic woodpecker bill; white on the cheeks and forehead; a red crown and a soft yellow throat. Other physical characteristics to look out for are the white rump, white belly with thin dark streaks along the flanks, a black tail and a body length of 8 inches. An adult male Acorn Woodpecker’s red cap merges directly with its white forehead. The females differ in that there is a black section separating the white forehead from the red cap.

As implied by its name, the Acorn Woodpecker’s preferred diet consists of acorns. They will also dine on insects, fruit, sap and nectar. They have also been known to feed on grass seeds, bird eggs and lizards. Foraging typically takes place near the tree canopy and the woodpecker species will seldom be found on the ground. The bird will either remove single acorns from a tree or they may remove an entire twig with up to 3 acorns attached. Sap is eaten as a group with all family members gathering at the sapsucking holes. Acorn Woodpeckers are known for storing acorns for the winter months. The nuts are carefully stored in what is referred to as a granary. A granary tree may be a dead tree or a very old tree with thick bark. Holes are drilled into the tree, some trees have had as many as 50,000 holes counted on them. By living in groups, the Acorn Woodpeckers are able to gather large quantities of nuts as well as defend their stash.

Due to their diet and method of storage, Acorn Woodpeckers are usually found in pine-oak woodlands, riparian corridors, hardwood forests and suburban areas with many trees. They are permanent residents and therefore do not migrate at all. Reproduction rituals can be quite complicated amongst Acorn Woodpeckers. Whilst some are monogamous, other groups engage in cooperative polygyny. Groups may have up to 7 breeding males and 3 egg-laying females. Females will lay their eggs in a joint nest cavity. Nest cavities are located within trees and are gently lined with wood chips. Eggs are white and elliptical in shape numbering up to 6 in a clutch (that of the entire group). The incubation period of Acorn Woodpecker eggs is 11-12 days with both females and males involved in incubation. Nestlings are ready to leave the nest cavity after 30-32 days.