Look for their large nesting colonies on cliffs as well as on buildings and under bridges. Polytypic. Length 5.5".

Adult: square tail; orangish buff rump; dark cap extending below eye; chestnut cheeks, sides of neck, and throat; bluish black on lower throat; cream to buffy forehead patch. Underparts, including flanks, whitish. Juvenile: similar to adult, but entire head usually dark brownish black, sometimes with small pale grayish, whitish, or rusty forehead patch. Rump paler buff. Chin and upper throat pattern quite variable, some mixed with white, full black, gray, or cinnamon. Flight: short triangular wings and square tail. Whitish underparts and paler underwings contrast with dark head and throat. Hybrid: very rare; hybrids with the barn swallow and tree