This bird gave the "whit" call; it was foraging low down in brush; also compare the tail (longer) and primary extension (somewhat shorter, though view here a bit obscured) with the Hammond's Flycatcher at http://www.pbase.com/tgrey/image/112229151 . The difference in calls ("whit" vs. "peek") is generally thought the most reliable distinguishing feature between the two Empidonax flycatcher species that regularly summer at Yuba Pass