When having a bluebird house, there are several very important things you should do to help maximize the chances of a successful fledging. General Tips - Put up your bluebird boxes by mid March. Make sure they are clean and ready to go. Do not take down your boxes after just one fledging.
Bluebirds breed more than once a year.
After a fleding, you should clean out the box though. You should leave your boxes up year-round in clean condition when not being used. The reason is that bluebirds look for nest boxes at all times of the year. If they come through your area and there is not a box up, they may pass by next summer since they had no success before. Monitor your nest boxes.