This bird was photographed in the middle Florida Keys, Aug. 13th. It was larger than a Northern Mockingbird. We see Northern Mockingbirds often here, and this bird did not behave like one, was bigger than one, and was ruffled (so marking difficult to decipher. Its a tough one, please give a guess. There are a few more photos at the link.
Sorry, I had to put a link since inserting an image doesn't work.
http://viewmorepics.myspace.com/index.cfm?fuseaction=viewImage&friendID=414169944&albumID=1212617&imageID=17051452