By chance, I tuned to the owl nest box channel on my TV this morning around 1:20 AM, and noticed a screech owl's head in the entryway. The owl spent a long time there, staring at various things, then jumped onto the perch inside the box. From there the owl did a lot more staring at things, and finally hopped down to the floor of the box. There, the owl began shoving and kicking the bedding material toward the sides of the box, in order to create a depression in the middle. Once that was done, the owl returned to the entryway, and exited several minutes later. The whole visit probably lasted 20-30 minutes.
This screech owl was obviously a female making preparations for egg laying (creating that depression in the bedding is as close as screech owls come to nest building). So, I don't know when nesting will begin, but it looks very likely that there will be nesting in the box this year.