I shall critique the wolf since I don't know much about crow/bird anatomy. First compliments...I really like how you used several colors in the wolf's fur and tied them to the background. It really gives it a connected feeling.
The wolf's eye could be a little farther back on his head and a little lower. that would enhance the slope of his muzzle. you could also make his mouth line and lower it a bit making his upper jaw even larger than his lower jaw. his nose could be a bit bigger too...just a little bit though.
His forepaws are a bit too small and his front legs could be angled a smigey bit.
one last thing...His hind leg that's mostly hidden by his other leg doesn't need the angle you gave to it. You could repeat what you did with the forelegs and place the one farthest away on the right side but that may make him look off-balanced. I agree with where you placed it just take off that angle...wolves don't have a joint there.
This is a great piece. I was being really nit picky and hopefully it'll help. Simply, beautiful done.