Terrific news! Don’t be surprised if they “disappear” for a few days or even 2 weeks. Normally if they are going to have another clutch it is 2-3 weeks after to give the female chance to recover. No guarantees though BUT they will likely be back next year! Just be sure nothing else wants to nest in the box. I had a House Wren that get stuffing the first box with sticks. The Blues picked another box that now has 4 – 4 day old chicks! Congrats!! It’s such a thrill to help these beautiful songbirds isn’t it!!?? 
