We have since returned to Camelback, camera-in-hand, but have been unable to recapture that great first experience (or see them there at all). I see the Blue-Grays around at the Desert Botanical Gardens a lot, but they fancy the larger, more dense trees there and also seem to prefer staying well behind the "Staff Only" gates. I guess we used up our quota of Gnatcatcher luck that wonderful day on the mountain, so for now I must be patient.
*Update* I got some good shots on 11/12/2011, which are posted below.
White feathers on the underside of the tale are diagnostic of a Blue-Gray Gnatcatcher, even if the rest of the body seems just black (like the Black-Tailed Gnatcatcher).
I absolutely love this chalky blue coloring. Its soft, a bit muted, and totally unique.
Early Gnatcatcher Photos