I saw two of these this evening in Cumming, Georgia. (Just north of Atlanta)
They were making a fairly soft, high pitch single syllable call. I originally called them as Eastern Wood Pewee, but now I think they may be Willow Flycatchers based n the grey color neck and grey chest band. But, I know I do NOT know flycatchers well, so I know I have a lot to learn and this would be a great place to start!
These photos are both the same bird. One in direct sunlight (late evening) and one in shade.
Thanks for the help!