Nice bird! I'm guessing this is with the big, slow Sigma you have? The branch seems to be in pretty decent focus, but there's (I think) motion blur on the bird. I'm guessing the bird didn't understand the instruction to hold still, and with the slow lens, it's hard to get the shutter speed up enough to compensate for mother nature's shortcomings.
Lighting is lovely and this looks to be a stunning bird. Focus is a bit soft and it would be nice to see him against a different background as he's kinda lost here. I also see sensor dust problems in lower left.