I'm shooting the 60D with a canon 100-400mm lens. Just bought the canon 1.4x extender, but haven't used it yet. I also have a bogen 3021 tripod from years and years ago when I tried film photography and did some birding. Recently bought a monopod. I'm certain I have the right equipment to get some incredible bird shots. I mainly interested in shooting the larger birds such as ducks and geese, hawks, but wouldn't hesitate to shoot songbirds; warblers and such. I've taken lots of shots (primarily hand held) learning the camera, but still have more schooling to do. I'm wondering if part of my problem is that I'm shooting at too far a distance. I'm cropping in 80 to 90% on most pics. Is this much cropping typical. Is there as rule of thumb to help guide me on how close I should be with a certain focal length lens.