I agree with David don’t give up yet. Just today I had mama blue looking at a box. Her second brood fledged 18 days ago. Normally she has an egg laid 2 weeks later, but we have had weeks of rainy weather. I think the weather delayed her plans. Mosquitoes are so bad here ….sure hope all the birds get busy eating them. We can’t do anything outdoors without getting attacked. Good luck.