All three species of North American bluebirds are secondary cavity nesters that readily accept nest boxes. Typically, all three are socially monogamous, with a single male and a single female defending a territory against intruding conspecifis and alone raising their offspring (Guinan et al. 2008, Gowaty and Plissner 2015, Johnson and Dawson in press). Both parents provision nestlings for 17–22 days, and the young continue to rely on the parents for protection and food for several weeks post-fldging (Guinan et al. 2008, Gowaty and Plissner 2015, Johnson and Dawson in press). Pairs that raise a fist brood early enough in the season usually make a second attempt (Guinan et al. 2008, Gowaty and Plissner 2015, Johnson and Dawson in press).