The male bluebird finally went all the way into the nest box today. These trailcam images don't show that moment, but show there has been a lot of activity there since last night. The last image shows the male with something in his mouth. To feed hatchlings? The last two images show a visit by a magpie yesterday and another nocturnal visit by a cat last night. Hopefully the hole is small enough and the box is secure enough to keep them out.