Cordilleran Flycatcher (Empidonax occidentalis) [XC622751]
by from Strayhorse Campground area, Greenlee County, Arizona, United States (call)
Cordilleran Flycatcher (Empidonax occidentalis) [XC841919]
by Sue Riffe from Weston Pass Rd, Park County, Colorado, United States (call)
Subspecies
Formerly treated as conspecific with Pacific-slope Flycatcher (Empidonax difficilis). Separated on grounds of differences in voice, morphology and allozymes, but this treatment questioned by some authorities. Further study is required. Geographical variation in size and colour is perhaps clinal.
The following 2 subspecies are recognised:
hellmayri Brodkorb, 1935 - Breeds interior western North America from southern Canada (west-central Alberta, northern Rocky Mts region) and USA (south to north-eastern California, southern Nevada, central and south-eastern Arizona, south-western Texas) south to northern Mexico (Sierra Madre Occidental of Sonora and Chihuahua, and northern Coahuila). Winters Mexico.
occidentalis Nelson, 1897 - Highlands of Mexico, from Durango, south-eastern Sinaloa, south-eastern Coahuila and Nuevo León south to Guerrero, south-central Oaxaca and western Veracruz.
BirdLife International Species Factsheet