Shoot wildlife photos in RAW, not JPEG. RAW files contain full sensor data with more dynamic range and shadow/highlight detail, giving you far more flexibility to adjust exposure and recover information during editing without losing quality.
I just want to mention that if you're not already shooting in RAW, you need to start because JPEG images are basically a computer rendition of what you wanted to take. So if you're taking the time to go and shoot in manual mode or even in shutter priority, I mean, even in automatic, you really should be shooting in RAW. Because it captures more dynamic range, captures more information in the shadows and also in the highlights, so that when it comes right down to editing the image, you have more room to edit.
