Kirk Roth
Rarely to be taken seriously
Weird. I wonder why they would be declining in WI and increasing in OH. climate related maybe?
The conventional thinking is that Bell's Vireo has been experiencing climate-related increases in range, not decreases. And that would include Wisconsin - note that their range map in the 1st edition of Sibley (2000) barely touches the state. Now they are a regular breeding bird north to the Twin Cities.
Head to some shrubby areas at Sauk Prairie in May or June and brush up (so to speak) on their song. You can find them.