Help with ID please

Seen this little guy yesterday and have never seen it before and haven't been able to locate it in any of the books that I have. I observed him being fed by what I believe to be a chipping sparrow but this bird was atleast twice the size of the sparrow. I looked up juvenile chipping sparrows and didn't look like one. Help appreciated.

http://img404.imageshack.us/img404/8629/unkown1of1.jpg

http://imageshack.us/photo/my-images/832/unkown2of1.jpg

tried to post another picture of it being fed by chipping sparrow but wouldnt show up

This is a young Brown-headed Cowbird, Justin. They lay eggs in the nests of other species and split, so the Chipping Sparrow was the victim and cares for the cowbird as one of it's own.

I agree with Dan on the ID as Brown-headed Cowbird.

Wow, thank you for the information.