I normally would like to be monitoring the boxes weekly, but this spring has found many gardening programs, activities, and other non-bluebird tugs on my time.
Bluebirds thrive in the Garden's varied habitats of meadows adjacent to woods, and we've had bluebird boxes up for many years, recently replaced a couple of years back thanks to a Youth Build program based at our university.
We usually have 12-18 successful broods per year from our eleven Garden boxes, with occasional casualties due to black rat snakes (our boxes don't have baffles).
In our home landscape, we don't have the right habitat for bluebirds, although occasionally we'll see one investigate. They're lovely birds and have their populations have rebounded with increased placement of boxes to replace the lost natural cavities that they would otherwise use.
The bluebird image is from a Nature Conservancy birding journal -- quite nice. I wish I could credit the artist.