Black-throated Grey Warbler (Setophaga nigrescens) [XC372844]
by from Red Box to Valley Forge Campground, Angeles National Forest, Los Angeles County, California, United States (song)
Black-throated Grey Warbler (Setophaga nigrescens) [XC466407]
by Bates Estabrooks from El Pescadero, Baja California Sur, Mexico (call)
Subspecies
Closely related to the superspecies formed by Golden-cheeked Warbler (Setophaga chrysoparia), Black-throated Green Warbler (Setophaga virens), Townsend's Warbler (Setophaga townsendi) and Hermit Warbler (Setophaga occidentalis). Hybridization with Townsend's Warbler (Setophaga townsendi) and with Hermit Warbler (Setophaga occidentalis) reported. Subspecies halseii considered invalid by some authors, although nucleotide-sequence divergence between the two subspecies is similar to that between Townsend's Warbler (Setophaga townsendi) and Hermit Warbler (Setophaga occidentalis).
The following 2 subspecies are recognised:
nigrescens (Townsend, 1837) - Breeds south-western Canada (southern British Columbia) southern on coast and in coastal mountain ranges of western USA to northern California; migrates to wintering areas mainly in western Mexico (southern Sonora south to Oaxaca).
halseii (Giraud Jr, 1841) - Breeds in western USA east of the Cascades (from Washington and Wyoming south to California and New Mexico) and extreme north-western and northern Mexico (northern Baja California, extreme north-eastern Sonora); most migrate to western Mexico (including southern Baja California).
BirdLife International Species Factsheet