Most Blue-and-white Swallow nesting activity occurs in January to June or July; however, in Colombia breeding peaks occur in September to December, February to April, and June to August; and in temperate parts of South America breeding occurs from October to February (Turner and Rose 1989). Two broods are sometimes raised (Skutch 1952).
The nest is made of grass and feathers placed in a crevice, burrow, or otherwise closed space. Blue-and-white Swallows have been found to use an array of cavity types (Skutch 1952; Turner and Rose 1989), including holes in trees, burrows in banks, road cuttings, crevices in cliffs, holes in walls or bridges, even, and artificial structures. Skutch (1952) found burrow nests back 10 to 23 inches from the mouth. Burrow nests frequently include those abandoned by the vizcacha, a rodent (Skutch 1952).
Eggs are glossy and pure white, with no markings (Skutch 1952). They are pointed and measure 17.2 x 12.5mm, with slightly larger size in Chile (Turner and Rose 1989). Blue-and-white Swallows lay two to four eggs in Costa Rica and Colombia; two to three eggs in Venezuela; five to six eggs in Argentina; and three to six eggs in Chile (Turner and Rose 1989). Both the male female incubate the eggs for about 15 days (Turner and Rose 1989).
Skutch (1952) described the appearance of nestlings as they grow. Upon hatching, nestlings are only show sparse down with tightly closed eyes. At four days dark points-the beginnings of feathers-show under the skin. At nine to ten days they begin to gain a cover of feathers. They fly from the nest at about 26 or 27 days.
Both parents feed the young. Feeding rates average three per hour for each nestling (Turner 1983). After fledging, young remain nearby the nest as parents continue to feed them for a few days (Turner and Rose 1989).