Changing my position a few yards, I was able to get a better view of the nest. Unfortunately the angle was such that I was not able to see into the nest, but two of the chicks were perched at the edge. (I heard there are three, but I only saw two myself.) One of them was especially vocal and was flap-hopping around the ledge. Its wings looked developed enough that it probably will not be in the nest much longer. The adult made one delivery to the nest in the few minutes I was there, accompanied by even louder screaming.
Unfortunately my photos of the nestlings are not so good. I probably would have gotten better results on a sunny afternoon. I am not giving the exact location for this nest since it is still a state endangered species.