Warbler, Audubon's, male, non-breeding to breeding plumage (Dendroica auduboni) - 20 Feb 08 - San Diego Zoo Wild Animal Park, CA. Note hint of yellow on chin. Considered a subspecies of the Yellow-rumped Warbler by some sources. The subspecies of the Yellow-rumped Warbler were split into four species by "Birds of the World Recommended English Names" v2.4, March 2010.
