Cordilleran Flycatcher - Region 5
Unless a specific vocalization is heard (the high-pitched two-note phrase with the second note much higher), these can only be presumed to be Cordilleran Flycatcher as Pacific-slope Flycatcher cannot be ruled out.
Typical Range
Photo by Sheridan Coffey
Cordilleran Flycatcher - Bexar Co., January 16, 2016. This "western" flycatcher was studied well but was not known to vocalize.