The range of Brewer's Blackbird, map courtesy Birds of North America online. Look how close it comes to Ohio as a breeder in Michigan. There as yet is no Ohio breeding record, but I think that this species could well be found nesting here. Extreme northwest Ohio is the place to look, and Williams County would probably be the numero uno hotspot. I think next year it is time to organize a "block-busting" weekend in Williams County and finally pin this species down. We'd find lots of other interesting species as well.
Below is a piece I wrote about possible new additions to the Ohio breeding bird roster, published in the inaugural edition of the Ohio Breeding Bird Atlas II newsletter. I hope that the prediction comes true!