I will start a new thread since it has been a while. I hope you will join in with whatever you have a photo of and want to share it with us. We don't get real technical but we do have our own resident bird expert. Kim (duckmother) very kindly is teaching us to identify some of these birds at whatever state they are in at the time. I had no idea they molt look different molt again look different. grow up to breeding look different again. and most young boy birds look just like their mom instead of their dad until they grow up and want a honey. Have I totally confused you? I am , I never say this is a certain bird without doubting myself. So just ask Kim she knows.
This little bird is a Northern Parula I think he may have had an encounter with the birdie in the window.