Here are a few steps in my new drawing of a Cape Buffalo and an Oxpecker bird. The first drawing shows how I get the entire basic shape of the animals down first and then I work on the eyes. If the eyes aren't right, the drawing will fail even is everything else is correct. I put together several photos in Photoshop to use for reference: adding the top of the horns which weren't on the original photo by dragging them from other photos, then adjusting the shape and angle so they looked right. Then I found several photos of oxpeckers and added the bird on his head.In the next shot you can see I have added much more detail to the center of his massive head!
This shot shows a closeup of the little Oxpecker.