This is a fledgling chipping sparrow, Spizella passerina. Based on location, he must be S. p. passerina. He's close to two inches tall in this photo. Taken in Anne Arundel County, Maryland. Reminds me of one of my favorite children's books, "Are You My Mother?".
I found his parents and siblings and released him after giving him a treat of waxworms, and taking his picture of course. Unlike mammals, most birds cannot smell and thus will not usually abandon young that have been touched by humans...not that it's a good idea though. I stuck around to make sure they fed him.