Western Bluebird (Sialia mexicana) [XC356721]
by Frank Lambert from Mount Laguna, Noble Canyon trail, San Diego County, California, United States (flight call)
Western Bluebird (Sialia mexicana) [XC172425]
by Lauren Harter from Walker Ranch, Boulder County, Colorado, United States (song)
Subspecies
Geographical variation relatively slight, but individual variation rather wide and some accepted subspecies possibly untenable. Proposed Mexican subspecies anabelae (northern Baja California) and australis (southern plateau) considered indistinguishable from, respectively, occidentalis and nominate.
The following 8 subspecies are recognised:
occidentalis Townsend, JK, 1837 - South-western Canada south to north-western Mexico (northern Baja California).
bairdi Ridgway, 1894 - Interior western USA south to north-western Mexico (southern Sonora and north-western Chihuahua).
jacoti Phillips, AR, 1991 - Southern USA (Davis Mts, in southern Texas) and north-eastern Mexico (San Luis Mts).
nelsoni Phillips, AR, 1991 - North-eastern and central Mexico (northern Coahuila to western San Luis Potosí, northern Guanajuato and north-eastern Jalisco).
mexicana Swainson, 1832 - Central Mexico (Veracruz to northern Puebla and Hidalgo, west to Michoacán and Aguascalientes).
anabelae Anthony, 1889 - Mountains of northern Baja Calif. (Sierra Juárez and San Pedro Mártir).
australis Nelson, 1903 - Southern plateau of Mexico (Jalisco to Morelos, Puebla and Veracruz).
BirdLife International Species Factsheet