Scot, I am a new bluebird box landlord, so I am no expert, but my bluebirds built a new nest in the same box immediately after a completely failed nesting attempt. The female originally laid 4 eggs and incubated for about 23 days and then abandoned the nest. I removed the nest and eggs once I was confident she had abandoned it, and the very next day they started building again! She laid 5 eggs this time, and 4 of them hatched. So I think you have a good chance of the pair nesting again. Good luck!!!! It’s such an exciting experience – but definitely an emotional roller coaster at times!
-Lori