There is little to no information on the net about how to use a monopod and ball head for bird photography. The scant references to it say that it is not a good idea and instead recommend a pan tilt head. However, you will often see monopods with ball heads being used by photographers in the field. In talking to one, I noticed his configuration was to have the ball head in the gimbal position with the camera lens collar mount on the side. This works only for larger lenses with lens collars. Initially, I thought the setup was a clear misuse of the equipment and almost mentioned it to him. However, I got so tired of horsing my lens on the monopod ball lens in friction mode that I decided to try his method. I can say that it is dramatically better. Holding the grip on the monopod with one hand and the other on the camera is much more stable than the old way. This means that not only are images sharper due to less camera shake but the autofocus has an easier time to lock on to the target. The result is that bird in flight photography is much better and those long deeply cropped “miracle” shots are much sharper. It can mean the difference between getting an ID for a bird or discarding the image.
If there is a downside to the setup, it is in the friction for elevation angle changes. That means I usually push up the head slightly to relieve the stress. There is a ball head on the market with a bearing for exactly this mode but it is too rich for my budget. http://www.acratech.net/categories/ballheads.html In the meantime, I’ll make do with the lower cost alternative.