A Bird in the Hand . . .

This little guy flew into the window, but after a while recovered and flew straight to a nearby tree. Anyone know what he is?
Karl

Attached Image:

The beak says vireo, but nearest I can tell it may be a red eyed vireo: https://www.google.ca/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0CAcQjRxqFQoTCPWIhO_S68cCFccVkgodf5sGOg&url=http%3A%2F%2Fwww.billhubick.com%2Fphotos%2Fbirds%2Fred-eyed_vireo.php&psig=AFQjCNGDifaNnRP8yIeBz4rdi395MEBpjQ&ust=1441946293573329

https://www.google.ca/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0CAcQjRxqFQoTCOL2pJfT68cCFcsXkgodQPMAMA&url=http%3A%2F%2Fwww.lynxeds.com%2Fhbw%2Fphoto%2Fred-eyed-vireo&psig=AFQjCNGDifaNnRP8yIeBz4rdi395MEBpjQ&ust=1441946293573329

But, I see a hint of a yellow rump in the picture so maybe some other vireo.

If you contact an Illinois birding site they could most likely narrow it down for you.
Good to hear it survived. Cheers!