Ok, for starters, the shading & colours look great! I love The Blacky-Blue wolf's design & Colouring, they really contrast well. The shadow of the overflying bird also looks great, it put a slight hint of mystery into it, which I quite like
All up, I think you did a really good job on this! The only thing you cold fix would be the tree shadows, they seem somwhat.... round? :/ But still, it takes a lot of effort to do this sort of thing, so it's just a suggestion!
I give this a 9/10