Petrochelidon pyrrhonota

This swallow has a buffy rump, short square tail, dark throat, dark cheek, pale collar, and usually a white forehead. Length 14 cm, wingspan 34 cm.

Cliff swallows inhabit open to semiwooded habitat, cliffs, canyons, and farm country, generally near meadows, marshes, and water. They build bottle-shaped mud nest in colonies on cliffs, under eaves of buildings, under bridges, and similar sites sheltered by an overhang. Many return to same nesting area in successive years, but colonies tend to switch nesting sites between seasons, evidently due to a buildup of insect parasites in the nests. Cliff swallow commonly repair and use old nests.

Gregarious at all seasons. Periodically populations may decline drastically due to prolonged spring or summer rains and reduced food availability (Terres 1980). Parasitic swallow bug (Oeciacus vicarius) sometimes is abundant enough to reduce reproductive success in large colonies.

Completely new nests of cliff swallows are built over a period of 3 to 27 days (often a week or two). Egg laying may occur as early as early April in Texas and California, early May in Nebraska and Idaho, late May in Illinois, Massachusetts, and Pennsylvania, and early June in Arizona. At higer elevations in the mountains, most egg laying probably occurs in June. In southern Arizona, most eggs are laid in July with the onset of the summer monsoon. The peak of laying in Nebraska is in late May and early June. Clutch size is 2-6 (usually 3-5). Incubation lasts an average of 13-14 days. Young are tended by both parents, can fly at 20-26 days, may return to nest for the first 2-3 days after fledging. In most populations, the young have fledged by the end of July or slightly later in the mountains and southern Arizona. Young are dependent on parents for food for 3-5 days after fledging, after which they may be fed occasionally for several additional days.

Cliff swallows usually produce one brood per year, a few have a second brood (Turner and Rose 1989; Gauthier and Thomas 1993a. Breeding activity within a colony is closely synchronized (Silver 1995). Prolonged rains or dry weather may reduce breeding success or postpone nesting.

Nesting occurs in colonies of up to 1,000+ pairs (average is a few hundred).

Researchers in Nebraska found that cliff swallow residents within a colony frequently lay eggs in neighboring nests. Sometimes cliff swallows move eggs laid in their own nest to a nearby nest (by carrying the egg in the bill).