Williamson's Sapsucker (Sphyrapicus thyroideus) [XC451061]
by Andrew Spencer from Calaveras Big Trees, Calaveras County, California, United States (call, drumming)
Williamson's Sapsucker (Sphyrapicus) [XC328740]
by from Golden Trout Camp, Golden Trout Wildnerness, Inyo County, California, United States (drumming)
Subspecies
Has hybridized rarely with Red-naped Sapsucker (Sphyrapicus nuchalis).
The following 2 subspecies are recognised:
thyroideus (Cassin, 1851) - Southern British Columbia south through Cascade Range and Sierra Nevada to northern Baja California (San Pedro Mártir Mts).
nataliae (Malherbe, 1854) - South-eastern British Columbia south through Rockies to Arizona and New Mexico. Winters in south of range and south to south-central Mexico.