I think the mystery Hummingbird is solved. My friend Greg Lavaty came by on Friday so that I could help set up his computer, and if we really got lucky, to see the mystery Hummingbird that has been visiting my Coral Honeysuckle.
Fortunately the Hummingbird did appear and Greg and I captured several pictures. Greg felt 95% sure this was a female Rufous Hummingbird. The even better news is that I now see the Hummingbird every day. If she hangs around long enough for the Ruby Throatted Hummingbirds to appear, that could become very interesting. She is very possessive of the Coral Honeysuckle and will not go to any of the Hummingbird Feeders.