Hi! Cool concept. I like the idea of an owl lord 
So there's 2 main things I would personnally work on for this piece. First would be the anatomy of the owl and second would be the lighting.
For the owl, I don't know if you used any sort of references, but if you didn't I would recommend you find a few. It help make you make it more convincing and you might even notice certain details you hadn't thought of that will inspire new ideas. But really I say that because the way you did the wings on the side doesn't feel quite right.
Here's two examples
As you can see, we don't really see much of the wings.
As for lighting, you have a strong lightsource right behind the main elements. In a situation like this, the things in front of the light would appear darker since the main light source is behind. That is unless you have another light coming from the front. But in this case, I feel like keeping things a bit darker would help sell the fact that it is night a bit better. And then you can maybe subtely bring back some of the details in the shadow if the get lost.
So this a really rough paintover, but that's sort of what I was talking about.
I used some of the blue from the sky to do a bit of lighter shading in the shadow as if the color of the sky was reflecting on him a bit. And I also darkened the bottom and top edges to keep the eye more towards the center of the picture. I might give him some glowy eyes if it was my piece, but that's just my style
So overall that's it. Keep in mind that this is only how I would personnally do it. Tthere may be other ways that are also correct. I hope this helps in any way. Keep it up!
