Identificaciones de codyprimero

Active nest found well within range.

There are two subspecies of Empidonax occidentalis (Johnson 1980b), that are diagnosed on the wing chord, bill length, and various aspects of plumage saturation (Johnson 1980b, Pyle 1997c). Note that some subspecies were described initially under E. bairdi Sclater, 1958, but the type of that taxon is a specimen of E. affinis, the Pine Flycatcher (Van Rossem 1934d).

E. o. hellmayri Brodkorb, 1935. Includes E. o. immodulatus Moore, 1940. Breeds inland from northeastern California north and east to southern Alberta and western South Dakota and south to Sierra Madre Occidental of Sonora and Chihuahua in Mexico east to northern Coahuila [type locality = Boot Spring, Chisos Mountains, Brewster County, Texas]. Overwintering range is less well delineated, but includes mountains of Mexico (within breeding range and down to foothills on Pacific slope) from southern Sonora and Coahuila south to Oaxaca; on Atlantic slope from southern Nuevo León south to Oaxaca, and along Pacific coast south to northwestern Michoacán (Binford 1989a, Howell and Webb 1995, Russell and Monson 1998). Breast a relatively bright yellow; wingbars dark buffy (juvenile) to buffy lemon (adult); larger (generally, male P7 > 68 mm, bill > 8.2 mm), with the wing more pointed (see Johnson 1980b). Hybridizes with E. o. occidentalis in northwestern Mexico (e.g., Chihuahua).