... skee-dlees chis chis chis*
This is a Dickcissel. I think he's a classy looking bird. I think his coloring gives the impression that he's wearing an ascot and a snazzy yellow shirt with a grey vest. And he sings a lot. This one was at Northerly Island in downtown Chicago. More pictures of this little guy are at my bird watching blog which is here.
*Sibley's provides this as the phonetic spelling of this bird's song