Adding to this interesting discussion about the timberline sparrow, I saw
and heard an usual "Brewer's" sparrow several years ago. It was along
the umtanum road, on the way to wenas creek. It sounded like a cross
between a Brewer's sparrow and a clay-colored sparrow. It had all the
field marks of a Brewer's as opposed to a clay-colored; if I had known
abou the timberline sparrow, I would've paid even more attention to it.
I just wrote it off as an unusual sounding Brewer's.