Good pictures!
The favorite nest box of all at our place was on the edge of a field across from the barn. The bluebirds liked to sit on the edge of the barn roof & when I mowed the field, they would be flying after insects disturbed by the mower.
When their babies fledged, they would all sit on the top board of a nearby fence. Most times, I did not look in the box to count eggs or babies so the first time I could count how many was when they got to the fence sitting stage. The youngsters would hang around together for quite a while so we had small bluebird ‘flocks’ as the other nests were emptied as well - we have 7 bluebird houses. I am really happy to see bluebirds at our new place.
I wonder how many boxes they’ve used. I will probably clean this one out tomorrow to get ready for the next clutch. This is early enough that maybe we will have 3 clutches this year.