Attached is a record shot of a white-tailed eagle (unfortunately I had the wrong lens on when we saw it and by the time I'd got to the car and changed it was on its way)! At the time and on the uncropped photo we did not see the second bird (to the left on the photo). Given that it is only noticeable when heavily cropped and it was a 300mm lens it was obviously a big bird. Any ideas from the limited info - another w-t eagle, golden eagle, or other?