I am pasting in some comments I received from Bob Walters today about the difference between tiercel (male) and falcon (female):
I believe that the photos of the tiercel have led me to another clue to distinguishing one adult from the other. If you look at Mike's pic's, note that the area directly above the tiercel's bill is black, while in several screen captures that I have in hand (you too, I imagine) the falcon displays a white patch above the bill. So, the falcon is marked by the white spot, or patch above the bill and the buffy-tipped tail.
Mike's photos help to distinguish in other ways as well. I believe that the tiercel's malars are more "rounded" than the falcons. Her malars are more "pointed". The tiercel's legs and feet are definitely the orange-yellow variety ... the falcon's legs and feet are more of a lemon-yellow color.
The play of events on the next four pictures is as follows according to what Mike saw:
1. Falcon (female) screamed from ledge (calling for food maybe?) She gives up and leaves. Shortly after Tiercel flies in with prey, which you see in this pic.
2. Tiercel feeding, then falcon flies in with prey.
3. Falcon takes over feeding. Tiercel leaves with his leftovers.
4. Good shot of falcon with the white above the nose as Bob pointed out.