We have a lot of these little birds in our backyard during the winter months. They have long had the name, Oregon Junco. I wondered why some bird books list only the 'Dark-eyed Junco, and learned the reason why from the website, "The Oregon Encyclopedia" -
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Here is what it has to say about the Oregon Junco:

"Juncos have considerable geographic variation, and many North American Juncos once treated as separate species are now known to freely interbreed where their ranges overlap. Thus, the Slate-colored Junco of the East, the Gray-headed Junco of the Southwest, the White-winged Junco of the Black Hills of South Dakota, and the Oregon Junco were combined into a single species and given the name Dark-eyed Junco (Junco hyemalis)."

"Regardless of the season, Oregon Juncos are one of the most common birds in the state and are fixtures at backyard feeders in winter. In the breeding season, they can be found in the understory of coniferous forests, from ponderosa pine to mountain hemlock and from Douglas-fir to lodgepole pine. Where more open habitats typically support two or three breeding species of sparrows, only the Oregon Junco lives in the deep shade of the dense forests. Unlike many of the state's breeding birds that travel to Mexico or beyond for the winter, Oregon Juncos may spend the cold months in the lower forests in the foothills and in hedgerows on the valley floor."