Common Name
ACORN WOODPECKER

Scientific Name
MELANERPES FORMICIVORUS

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Photo by Jim Weis
Photo Courtesy of Utah Division of Wildlife Resources

The acorn woodpecker, Melanerpes formicivorus, ranges from northwestern Oregon to Colombia. It does not migrate. Its habitat is oak woodland and mixed oak - coniferous forest. This species eats mainly acorns, fruits, insects, especially flying ants, and sap. It stores food, including insects, and has the unique habit of storing acorns in individually drilled holes in tree trunks or wooden structures, such a utility poles and buildings. A single granary tree may be used by groups of acorn woodpeckers for many generations and may contain up to 50,000 such storage holes. Typically each hole is filled with an acorn, or other nut such as a pinyon nut, in autumn. Such stores of acorns are of critical importance in temperate regions, allowing this species to overwinter in areas where food availability in winter would otherwise be limiting.

The nest is in a hole excavated in a tree or utility pole, usually twenty to twenty-five feet above the ground but sometimes as low a five feet or as high as sixty feet. These birds breed communally in groups of up to sixteen individuals, typically about three to six, that help at a single nest. There are usually about four to six eggs, but larger clutches are not uncommon and probably are produced by more than one female. Incubation is by both parents and occasionally by other members of the communal group as well. The eggs hatch after eleven to twelve days. The altricial young are tended by the entire group; they leave the nest after thirty to thirty-two days and become independent after another month.

Sources:

  • Koenig, W. D., P. B. Stacey, M. T. Stanback, and R. L. Mumme. 1995. Acorn woodpecker. Birds of North America 194: 123.

  • Baicich, P. J., and C. J. O. Harrison. 1997. A guide to the nests, eggs, and nestlings of North American birds. 2nd ed. Academic, San Diego. 347 pp.

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