I went down there this morning as soon as I could, and just got back (11:07 MST). I saw the falcons after about 5 minutes, coasting on the wind, and playing aerial tag, so all was well with them. I waited and waited, and finally saw the ravens; I was not at a very good angle, but I think the female went into the nestbox and, then I saw the male, who flew over and perched near the nestbox but on top of a ledge; his eyes were glued to the skies for a while, then he flew onto the roof, where I could not see him anymore, so I don't know if he stayed there or not.
They have only one lonely egg in the box, and yet they still try - I guess it is the biological imperative; either that, or they are very stubborn birds.
I will try to get down there again later today - I have a box and a towel, just in case.