I would say it’s a Chipping Sparrow (an adult in fall/winter plumage) as originally suggested for the following reasons:
- A first year White-crowned Sparrow would have a broader crown-line, the eyebrow would be a little whiter in colour, and the area below the eye (the cheek) would be a little lighter, more the colour this bird is above the eye.
- A Field Sparrow does not have a strong dark eye-line at any time of it’s life, which this bird clearly shows.
Just my 2 cents.
Walter