There a strong similarity between wildlife photography, none of it make it easy.
Both genres involve fast moving subject, often with erratic and unpredictable movement. Both involve making images from a safe or manageable distance. Low light is often a problem and this only serves to compound the difficulty.
That being said, I still remind myself that the great action and sports photographers of the past nailed their awesome images with the simplest of manually controlled cameras. Yes I'd really like a 1DX for Christmas but really I am so grateful to have the gear I have even with its limitations which not so long ago were true marvels of imaging innovation.
Photo: Robert Rath, '366 Days of 2012, Day 298 - Talons'. 1/800s f/2.8 ISO2000 2000mm