Gilded Flicker

The Gilded Flicker is one of three Northern Flicker subspecies, and is found only in the southwest. It sports the red mustache of the Red-Shafted subspecies, but has the yellow rachi and feathers of the Yellow-Shafted.

The yellow rachis, which is sort of like the stem for the feathers, is visible when the Flicker is perched. Since you usually only see the yellow flash of the underside feathers (of the wing and tail) as the bird is flying, observing the rachis is the next best way to identify which species of Flicker you're observing.