I captured my first Slate-colored Dark-eyed Junco photo in April of 2015. They returned that fall in mixed flocks with sparrows and Oregon Juncos. I've had the fleeting sense that I've seen them before but every photograph I'd taken turned out to be Oregon Juncos. Some of my captures from fall have birds with white wingbars. These could possibly be White-winged Juncos whose range is normally in the Rockies but the similarity of overall size and bill shape to Oregon Juncos most likely makes them the 1 out of 200 Slate-colored with white wingbars.