These birds excavate a nesting cavity in termite mounds on the side of trees. They fly in from a nearby tree and have a dig for a bit then fly back. To get this shot I set my AF expansion four focal points at the top right of the frame as the bird was flying in from left to right. I held focus on the landing spot viewing through my right eye while watching for the bird flying in with my left eye. When I saw it coming I held the shutter; I was about 15 meters away. These birds are flying missiles so I had barely half a second to get some shots all the while standing on a 35 deg slope holding the 6 kg camera/lens steady for up to a minute or so. Interestingly I later discovered that these birds were at the same time feeding young in another nest nearby so I repeated the process there and will post a shot from that session later. All up over five days I spent about ten hours at this and got a few keepers.
1DXII 400mm F/2.8L II 1/5000 f4 iso2000 ev +0.7 early morning to get the best light penetrating the tree cover and needed the high iso to get the shutter speed up to stop those fast wings. DPP PS about a 50% crop S&H and light sharpening.