How long is the gestation period for a blue bird?

Bluebirds do not have a gestation period, which refers to the length of a pregnancy. As birds lay eggs, they do not have gestation, but an incubation period, which refers to the length of time an egg is kept warm until it hatches. The incubation period for bluebird eggs is 12-14 days, but incubation may not start until a week after the first egg is laid, in which case the period can extend to 19 days.