When photographing wildlife, the image works best if you have supporting color around the image. I like to blur the background and make it a color pallet. Below are some images where the focus is clearley the subject and its action while the enviroment is softened so its color is what is supporting the subject.
The way we achieve this is to shoot with a shallow depth of field. In many cases this means to shoot wide open. If you have a F/4 lens,shoot at f/4. I like shooting f/2.8 depth of field.
Many of my fellow photographers feel with the advent of great high ISO capabilities we no longer need to invest in super fast glass. i.e.: f/4.0. f 2.8 and larger. I on the other hand feel the creative chose of shallow depth is even more important in chooseing f/4 and f/2.8 lens.
The side benifit is you get fast shutter speeds without having to increase the ISA as shown above. The lower the ISO the cleaner the image so the faster the glass the better results. Look for color behind your image and blur it out for a great color pallet.