After I had done closing the box back, he checked out the box itself as if to give the all clear.
Then the female checked it out as well. She began bringing nesting materials again.
If you look closely, you can see a dark spot near the center of the picture, just in front of the tall broom sedge. It's the female bluebird gathering dried sedge or grass or straw. (The other spot near the drive is a sparrow or junco foraging.)
At one point, she had nest materials to place while the male was inspecting the box. Two or three times she fluttered in front of the box, waiting for him to move. He finally went inside and she went in as well. He soon flew out, and I could imagine her carefully arranging the straw in the nest.
Meanwhile back at the ranch, a white-throated sparrow was having a rather brisk bath.
There is lots of bird activity. Spring can't be far behind.