Northern Prairie Wildlife Research Center
HABITAT: Breeds in deciduous and mixed deciduous-coniferous forests in the eastern and northern parts of its range, especially in woodlands with Populus. In the Rocky Mountain region, occurs primarily in aspen forests or in coniferous forests where aspen is present. Uses a variety of forests and open woodlands, parks, and orchards in winter.
SPECIAL HABITAT REQUIREMENTS: Dead or live trees with heartrot for cavity nests.
NEST: Excavates cavities in snags or in live trees with rotten heartwood. Prefers aspens but will nest in ponderosa pine, birch, elm, butternut, cottonwood, alder, willow, beech, maple, and fir. May use the same nest tree for several years, but excavates a new cavity each year.
FOOD: Drills rows of holes (sapwells) through the outer bark and consumes cambium and tree sap. Also eats a variety of insects attracted to the sapwells (ants are probably the dominant animal food). Fruits, mast, and Rhus seeds are included in the diet.
REFERENCES: Beal 1911, DeGraff et al. 1980, Howell 1952, Johnsgard 1979, Lawrence 1967, Thomas et al. 1979.