Northern Prairie Wildlife Research Center
HABITAT: Not confined to any single habitat, as breeding range is largely dependent on suitable nesting sites. Formerly found in habitats with mature, hollow trees, now occurs primarily in the vicinity of buildings in towns, cities, and around farms.
SPECIAL HABITAT REQUIREMENTS: Hollow trees or structures such as chimneys, silos, cisterns, wells, rafters, and airshafts for nest sites.
NEST: Originally adapted to nesting in caves and tree hollows, now mostly nests in man-made structures. Prefers dark areas and sheltered sites high above the ground. Constructs nest of twigs glued together with saliva; attaches nest to a vertical wall anywhere from near the top of a structure to more than 20 feet below the top.
FOOD: Forages almost entirely on flying insects including beetles, flies, ants, termites, and bugs but will sometimes take small caterpillars hanging from tree branches or leaves.
REFERENCES: Bailey and Niedrach 1965, DeGraff et al. 1980, Fischer 1958, Forbush and May 1955, Johnsgard 1979, Terres 1980.