Although I didn't plan to provide another update this quickly, I have a cool picture that I wanted to share.
I opened the nest box today to check for bluebird blowflies. BB blowflies are parasites that can live in the nest and feast on the babies. A adult blowfly (with red eyes) lays eggs in the box and the larvae which look like gray maggots which hide in the nest during the day and feed on the blood of the babies at night. My daughter has found them in one of her bluebird boxes just once. I found no blowfly larvae today.
While I had the box open I took this picture which shows the color of the babies that the in-box camera doesn't capture. The second picture from yesterday's posting is essentially the same picture but you can see today what the in-box camera doesn't pick up.