I'm sometimes amazed how animals evolve and what characteristics get passed on to subsequent offsprings. Over the years, I've observed lots of Dark-eyed Juncos, this is the 1st one with a completely white tail.
See 'previous' two images for additional views.
Nikon Z 6II
,NIKKOR Z 70-200mm f/2.8 VR S with TC 2X 1/400s f/9.0 at 600mm iso720
Free Crop of DX Image ReSized for Internet Viewing
full exif