Dark-eyed Junco Junco hyemalis
These two pictures clearly show the difference in plumage between a male and a first winter female Dark-eyed Junco. Both of these birds visit our back yard every day, but the female is alone among several males.
In fact, this species has three other recognizable subspecies, all of which look distinctly different from the Slate-coloured variant shown here. They are the White-winged, Grey-headed and the Oregon forms. Rarely representatives of these races show up in southern Ontario, much to the delight of birders.