Northern Prairie Wildlife Research Center
STATUS: Common in the West, locally fairly common in the East; overall populations are stable or increasing, except in some northeastern States where it is of special concern on the blue list for declining species.
HABITAT: Originally restricted to the vicinity of cliffs and banks; now occurs over open country around farmlands, towns, bridges, dams, freeway overpasses, and other areas near mud supplies and potential nest sites.
SPECIAL HABITAT REQUIREMENTS: A vertical substrate with an overhang for nest attachment, a supply of mud suitable for nest construction, fresh water with a smooth surface for drinking, and an open foraging area near the nest site.
NEST: Originally nested on bluffs, cliffs, deep gorges in mountains, and sometimes on the side of large pine trees and in caves; has adapted to building its gourdlike mud nests under the eaves of, or in, buildings, under bridges, in culverts, on the face of dams, and under freeway overpasses. Forms colonies of up to several hundred nests in favorable locations.
FOOD: Consumes insects caught while flying high, often above 100 feet, as nearly 100 percent of the diet.
REFERENCES: Beal 1918, Bent 1942, DeGraff et al. 1980, Emlen 1954, Forbush and May 1955, Johnsgard 1979, Mayhew 1958, Samuel 1971, Tate and Tate 1982.