The fourth one is trying to hatch. Here we go with my brilliant close-up photography. See how clear the trees are behind my hand? Well, anyway, the fourth egg has a little burst of cracks to the right of the shiny part, if you can make it out. If I am able to be out there and not bother the parents, I will try to document the fourth one hatching.
The thing that is weighing heavily on my mind is that the GD house sparrows are trying to build a nest in the purple martin house, which is not far from the bluebirds. If they get frustrated, they may come in and kill the bluebird babies and build a nest over their corpses. For the last time, SEE WHY I HATE HOUSE SPARROWS? They are a real danger to the nestlings.