I believe this to be a juvenile Brown Thrasher but I am not 100% certain....it's a new visitor to my set up. I took this very early this morning and it was cloudy as well so I needed high ISO and a slower shutter than I would like but this little guy held still for a few seconds. Please correct me if I am wrong on the ID.

1DX
500mm
ISO 3200
f/4
1/100