Common Yellowthroat (Geothlypis trichas) - HBW 15, p. 771

Taxonomy: Turdus Trichas Linnaeus, 1766, northern America = Charleston, South Carolina.
Forms a superspecies with G. beldingi and G. rostrata, presumably also including G. flavovelata; the four have sometimes been regarded as conspecific. Has hybridized with Oporornis philadelphia. Race chapalensis sometimes considered to represent a separate species. Geographical variation complex within huge range; up to 29 or more races have been described, many of these too poorly differentiated to warrant recognition. Recent work involving mitochondrial DNA suggests W and E groupings of present species may be closer to other congeners than to each other; further study required. Proposed races yukonicola (described from Jarvis River, in SW Yukon) and brachidactylus (described from "N provinces" of USA) sometimes regarded as worthy of recognition, but presently treated as synonyms of, respectively, campicola and nominate; in Mexico, riparia (described from Tesia, on R Mayo, in S Sonora) synonymized with chryseola, but possibly merits recognition. Type locality previously listed as Maryland, but this was based on reference to a 1702 publication now shown to apply instead to Dendroica dominica. Thirteen subspecies currently recognized.