Darrell, I totally agree with Tammy & Darrell – if you put up the box you must be willing to try to eliminate the HOSP. BUT, don’t let that scare you out of being able to enjoy the nesting season of the bluebirds by watching them build a nest, then the 1st egg being hatched, and the parents feeding the babies, and then those babies flying away like “big birds.” AND then later on to watch them “return home” after they are eating on their own (that is, if you feed them mealworms). There is nothing more satisfying than having this experience, ALMOST as exciting as watching your children grow up! If you are unsure about trapping at first, you need to begin with removing the HOSP nests and by using a sparrow spooker if you do get bluebird eggs. But, if you really want to have success, you will need to trap/dispose of the HOSP. Like Tammy said you may get by for a while, but it will eventually happen if you don’t take precautions. Good luck!
