How was it done? First of all the photographer used a really long lens (If I had to guess I’d say at least a 400mm lens. Might have used a 300mm f/2.8 with a teleconvertor. Of course there’s always the 600mm f/4 but who has got $12K – yes you read that right!) You can tell the lens is long because of the compressed depth of field. Second he (or she) set themselves up in a place where they knew the birds were fishing on a regular basis. Third they probably setup some sort of a blind so the birds weren’t scared off. Fourth they shot with high shutter speeds to freeze the action.