Incubation on track!
Well, it seems that Scout is now focused on incubation. It is possible there could be another egg, but four is the normal clutch size. We were able to get a better look at the egg laid yesterday and it appears to be intact, just lacking pigment on both ends. It's likely just a "cosmetic defect" and the egg should develop normally.
What to expect during incubation...? For the most part it will be watching a bird sit on rocks - basically, one of the adults will be on the eggs almost 24/7 for the next +/-33 days to keep them at a consistent temperature for development of the embryo. In general, not too dramatic! Scout will assume most of the incuation duty, while Trooper's role is to provide her food and take her place on the eggs while she eats.
However, we can expect some variation in the action: combine a south-facing ledge with unusually warm temperatures and there will be times, especially on bright sunny days, that Scout won't be as tight on the eggs, in fact, she may even shade them. This is to prevent the eggs from being too warm. In past years she has rolled them to a different location within the box and then back to the main scrape. So, there will be some different behaviors to watch for over the next several weeks.