Cliff swallow adult upperparts are bluish black with a buffy rump patch, white streaks on the back, and whitish-buff forehead. The tail is square tipped. The underparts are whitish with a dark chestnut to blackish throat. Voice includes a harsh chattering and softer churr and heew calls.
Similar species: Barn swallows also build mud nests, and both species sometimes fly together in mixed flocks. Barn swallows, however, are more slender, have a dark rusty (not whitish) forehead, and have a long, deeply forked (not squared) tail. Barn swallows are more likely to build their nests to barns, while cliff swallows are more likely to build nests on bridges.
Length: 5½ inches (tip of bill to tip of tail).
Statewide. In the western United States, cliff swallows nest under overhanging cliffs. With the construction of barns and bridges, this species has been able to move into many areas of eastern North America.
Habitat and Conservation
Usually seen as they fly in swarms around their clusters of juglike mud nests attached to overpasses, bridges, culverts, barns, and cliffs. Colonies of nesting cliff swallows may contain several hundred nests. In spring, people sometimes see them gathered around rural mud puddles, where they roll little bits of mud into a ball and fly off, carrying it in their mouth to the nearby nest they are constructing.
They forage on the wing for flying insects, such as flies, ants, bees, wasps, true bugs (including assassin bugs, leaf bugs, squash bugs, stinkbugs, and tree hoppers), many types of beetles, dragonflies, mayflies, butterflies, moths, grasshoppers and crickets — and occasionally berries. Open areas where insects are numerous, as over pastures, open floodplains, and lakes and ponds, seem to be preferred foraging sites.
Common but local summer resident.
Cliff swallows arrive in our state in April and return, in many cases, to the colony they were born in. Gourd-shaped mud nests are lined with plant materials and feathers. The structure they are attached to must have a fairly rough surface, a vertical wall, and a horizontal overhang. Clutches comprise 1–6 eggs, which are incubated 10–19 days. The young fledge in about 20–26 days. There can be 1 or 2 broods a year. With nesting completed, they depart for South America in September.
This is the same species that famously returned to Mission San Juan Capistrano in California. In the early 1900s, the mission’s leaders publicized the birds’ annual return to raise funds to restore the historic building. A popular song was written, and today there’s a festival for them each March.
Cliff swallows help control populations of many kinds of insects, both here and in the tropics where they overwinter. Their predators include hawks, falcons, owls, snakes, and house cats. External insect parasites can infest their nests to the point where the entire colony may relocate.