Mystery Bird: Chipping Sparrow, Spizella passerina

I have a theory that there is only one sparrow in Illinois, so this is obviously a chipping sparrow. Possibly in disguise.

I'm leaning toward a Spizella, and with the Mystery Bird, any Spizella should be assumed to be a Chipping Sparrow until proven otherwise. I can't see anything to prove otherwise, so I'm going with Chipping Sparrow, but with a low degree of certainty.

Oh, heh. I thought that shot looked familiar. How soon I forget...

Looks to me like something that's spreading northeast.

My Buntings and Sparrows book now falls open automatically at Chipping Sparrow. As there is a hint of grey(gray) rump I think it is this one.

hrm. perhaps i need to choose another LBJ as my pet project for 2010? i am open to suggestions, especially from CBC count coordinators.

on the other hand, maybe i should post a bird image and identify the species, then ask you all to ID the photographer?

winter Chipping: subdued version of breeding plumage, buff brown, with darkly streaked upperparts, greyish below; the cap also subdued looking more brown than red because of the dark brown streaking... there is enough of the bill visible to exclude: the American Tree, which would have a bi-colored bill (and more obvious white wingbars); Clay-colored, which would show a dark tip (and white supercilium/brown rump); and Brewer's, which would also have a dark tip to the bill (and no grey nape)...

Field should be excluded because it would not show any dark streaking on the head nor the dark eye line; and although Swamp is very close from this angle, it should be excluded as I would still expect to see more grey across the face and above the eye, and also more grey on the underparts...

although there is variability within the Western subspecies, because of location (and I see nothing untoward with this bird) this must be the "little finch-sparrow-sparrow", Spizella passerina passerina.

For comparison:

winter Field Sparrow

winter Swamp Sparrow

David -- you're right about the gray on the face of Swamp Sparrow. The supercilium shouldn't contrast with the nape, as it does on this bird. Also, the wings should be much more rufous, contrasting with the back, and the flanks should show a distinct buff color. Swamp Sparrows always look red and gray to me, more than brown.

Heh. I like the idea of posting a picture, and asking us to ID the photographer.