Two days ago, I was watching the Eastern Bluebirds when suddenly the female brought a green caterpillar to the nest. There must be baby birds in there!
She went in.
A minute later she came back out. No diaper! This could be because the parents are known to eat the fecal sacs of young baby birds.
A little while later, the father brought more food.
I took the last picture of the first brood babies on June 3. So 20 days later, these two parents have brought forth a second brood. Amazing, but credible. Eastern Bluebird incubation period is 10 to 19 days. So, it is quite feasible for this couple to lay their eggs and incubate them successfully between June 3 and now.