[cobirds] status of "Red-backed" Junco in Colorado

The other day, buried amid a mixed-subject post, I asked (so far unanswered) if anyone on this listserv knows whether the so-called "Red-backed" Dark-eyed Junco has occurred in Colorado and/or whether it has any history whatsoever of occurring outside its normal range of Arizona to West Texas.  This subspecies is Junco hyemalis dorsalis and is considered distinct from our reddish-backed breeder in CO (aka the "Gray-headed Junco, J. h. caniceps).   I had a junco with a bright red back patch at Crow Valley the other day that "looked different" and it just got me to wondering about this junco subspecies.  Thanks.

Dave Leatherman
Fort Collins