Cordilleran Flycatcher
singing bird on territory
Coahuilla, Mexico
15 June 1994

The most similar bird to this in appearance (teardrop shaped eye-ring) is Pacific-slope Flycatcher which does not occur in this area and has a different voice. Those two species used to be considered the same species, "Western Flycatcher"

This is a scan from a 19 year old slide, so the colors are somewhat dull.