Fox

Oscar, I like the direct stare from the fox and the way he/she stands out against the darker background. Exposure looks good. If this were mine I'd desaturate the greens a bit.

Doesn't look like the trusting kind. Just look at the suspicion in the stare. Neatly framed placing all emphasis on the fox.

I like his position in the frame and the rich colors, however to my eye the grass and background seem overly saturated, so some selective processing might serve you well!

Love the space and low angle here Oscar...
I think overall it suffers from a bit of a green and cyan cast. Easy to fix...
The fox definitely appears sharper in the larger version.

I like the way the fox occupies a small area in the large frame, and the fact that it is looking at the photographer. I, too, though, think that the colours are over-saturated, which is causing the grass to look too green and the fox too red!

Nice shot, but very oversaturated - not only the grass. The 200-400 in combination with the 1.4x is not the best recipe for sharpness, you need to stop down more than 5.6 to get decent sharpness. Handholding that amount of focal length at 1/125 is also not ideal for optimal sharpness. In a situation like this I'd go for a smaller aperture and raise the ISO a bit more - it's better to have a sharp image with some noise than a noisefree image that is not sharp. Hope that helps.