Terrific feather detail James! The bird is too tight in the frame for me; I'd particularly like a little more room to the right and up top. I think the bird would benefit from a little more brightness as well. It would be helpful if you would include the technicals on all your photographic submissions. Thanks for posting!
According to the exif embedded flash was used, but I think it could have been stronger as the bird looks a little dark. At 135mm this was rather close to your subject - is this a captive owl?