Audubon's Warbler or at least the _auduboni_ subspecies of the Yellow-rumped Warbler _Dendroica coronata_ This is the western subspecies. Last year there was talk of the Audubon's being split out of Yellow-rumped again but sadly that did not happen. Since its by far the most common wintering warbler for us, we tend to forget how beautiful it really is in breeding plumage. And the Audubon's subspecies is clearly more striking in my opinion. In natural light. Yosemite National Park, CA.