Again, you have painted something I love. I really like both the composition and the subject. Raven is one of my totem animals, so I tend to respond or react when I see images containing them.

Technically, there are three areas which I feel can be improved to give the painting a little more depth and realism.

First, I have to comment on the placement of the raven's feet. I get the impression that you used a reference where the raven was standing on something flat, however, his feet really should be curled a little more to make him look as if he is holding on to the branch as opposed to standing upon the branch.

Second, the addition of hinted background -- the inclusion of a few branches or hints of tree, painted in the same hues as the background, would give the painting a more natural depth.

Third, and finally, while the limited palette is lovely, the addition of shadow layer rendered with a wash in mayhap a blue or brown would again enhance depth and give the viewer a better sense of light and dark.