Chickadees Have An Active Nest

The nest in our so-called "bluebird box" (that keeps failing to attract bluebirds!) has not only attracted a nest builder, but an egg-layer.  And today I identified the species.  It was clear once I saw the eggs we were dealing either with a titmouse or chickadee.  Once I opened the box for inspection today I startled a---chickadee.  Mystery solved.  It is interesting that the chickadees used such a large box given their usual taste for tight little holes.  But so what?  The last user of the box was a d**n House Wren and I'm happy to see almost any other nest builder.  So we watch for another coming hatch...should be fun!