Most human-like robots don't even attempt biological accuracy, because replicating every muscle in the body isn't necessary for a functional humanoid. Even biomimetic robots based on animals don't attempt to replicate every anatomical detail of the animals they imitate, because that would needlessly complicate things. That said, there is much to be learned from how muscle groups move and interact with the skeleton, which is why a team at Tokyo University's JSK Lab has developed what could be considered the world's most anatomically correct robot to date.
The Japanese seem to be well ahead of everyone in robotics. This is the kind of thing I would do to build a robotic bird.