Have only had time to get out once with 1DX. Got to a pond in Central Park to shoot some of the local waterfowl. Here is a Mallard doing the typical wing flap after a bit of preening. Shot at ISO 1000 which I know is not high for this camera but I never liked the results of my 7d2 at anything over ISO 800. This picture is so much better than I would have gotten out of that camera.
Canon 1DX and Canon 500 f4ii. ISO 1000, F6.3, SS 1/1000. Tripod mounted while lying on some rocks.
Converted in DPP 4.5. In PS I cropped about 50%. Sharpened and used Neat Image for noise reduction on the bird and background.