This bird was giving the mewing call characteristic of juveniles of this species, sounding something like a Blue-gray Gnatcather. Note the yellow gape, visual evidence that this bird is a juvenile.

Photographed above the Gene Sheehan overlook off the Ipiwa Trail; this is Bell's Sparrow territory, but none were found this day. One of the most beautiful views in the Bay Area, west to the Pacific Ocean, and from the top of the ridge looking east, visible on this clear day were Mt. Diablo, Black Mt., Mt. Hamilton, and Mts Umunhum and Loma Prieta.