Vaux's swifts pair off around May shortly after arriving to the breeding grounds. In northeast Oregon swifts begin the construction of their nest during the month of June, while nest construction begins in May in western Oregon (Thompson 1977). Incubation occurs between mid-June and late July. Nestlings appear early July till early September. Fledglings develop between late July till early September. (Bull, Collins 1993)
As for parental behavior, incubation of the eggs starts only after the entire clutch of eggs is laid. Eggs are constantly wtached by both adults. Both adults share responsibility for incubating eggs. Mating and parenting is usually monogamous, but there are reports of three swifts feeding one brood. This suggests cooperative breeding, similar to that seen in the Chimney Swift. (Bull, Collins 1993)
Average time to hatching: 19 days.
Average eggs per season: 5.