Northern Prairie Wildlife Research Center
HABITAT: Inhabits forested regions with large trees. In Montana, it occurs in mixed forests of Douglas-fir, ponderosa pine, lowland fir, western larch, yellow birch, aspen, and cottonwoods; in California, inhabits ponderosa pine, mixed conifer, and Jeffrey pine forests, and possibly black oak woodlands. Also inhabits river valleys in dense Douglas-fir and redwood forests.
SPECIAL HABITAT REQUIREMENTS: Hollow stubs or snags for nesting.
NEST: Nests are usually in a tall, hollow, dead tree, or inside burned-out stumps, generally within 20 inches but up to 6 feet up from the bottom of the cavity. Also nests in chimneys, but is not dependent upon them.
FOOD: Feeds exclusively on flying insects captured in mid-air in forest openings, especially over lakeshores and streams.
REFERENCES: Baldwin and Hunter 1963, Baldwin and Zaczkowski 1963, Bent 1940b, Scott et al. 1977, Terres 1980, Verner and Boss 1980.