Very good pictures I too am trying get the most out of sharpness . I'm looking at buying light room 4 and a Mac for editing . I too would like to be able to call in varmints for few pictures
Here's what I've found for getting the best results.
1) Get close(r). Don't crop much. Cropping loses resolution.
2) Use the single center focal point. Put the point directly onto the eye of the subject.
3) Use the AI Servo (Canon's name for Continual AF) Auto-Focus setting for live animals.
4) Use a fast shutter speed (1/1000) or better. This means you'll need to use a higher ISO too. I'm getting decent shots even at ISO 1600 and in some cases, even higher.
5) My camera and lens are taking sharper images when the aperture is choked down a bit (f/7.1 to f/11) instead of wide open at f/4 or f/5.6. Again, this means higher ISO settings.
6) I'm using Canon's Digital Photo Pro (DPP) for processing. I've found that the Unsharp Mask (USM) tool works much, much better than the Sharpness tool. Under USM there's 3 adjustments; Strength, Fineness, and Threshold. I generally bump the Strength to 5-7, the Fineness to 7-8 and keep Threshold low at 2-3. You can bump Threshold a little when using high ISO but you'll lose some detail.
7) Apply Noise Reduction as needed. Again, the more you use, the more detail will be lost.
8) Go easy on Contrast and Saturation. A little goes a long way. In some cases, especially with hi contrast shots, I'm using -1 or -2 on Contrast. This helps to reduce the bright sky or highlights.
9) A little negative Shadow will help enhance details. I don't use more than -1 or -2. In high contrast shots (like a dark bird against a bright sky) I use positive Shadow (+1 or 2). This will brighten dark areas.
All of this assumes that you're shooting RAW images. Once you've processed the image go to File, then Convert & Save (not Save or Save As). Adjust to save a high quality JPEG at a (Image Quality) of 7 or 8 and a size of 350 dpi for posting to internet or higher for other uses. Go to 800 or 1000 if you're going to print the image. This saves your RAW file and produces a high quality copy in JPEG. You'll have to have a program that reads RAW files, such as DPP, Photo Shop or Lightroom.
Finally, understand how you AF works. Mine detects vertical and horizontal lines on the target. It then uses these lines to achieve focus. If the surface is smooth and/or without texture then the AF will search or miss focus altogether. The fine hair or feathers on the body of an animal often won't produce a enough texture to achieve a fine focus. The head/face/eyes have features that provide for better focus. Besides, viewers are drawn to the eye of the subject so it really needs to be in focus.
Hope this helps someone.