This is a beautiful piece, and one which incorporates romanticism with intellectual thought. The woman's expression looks calm and thoughtful while most of the attention and movement is drawn towards the birds. The choice of placement around her head is interesting, and it can have an array of resemblance. She could be allowing her thoughts to sour freely and fluently. This would be a meditative and spiritual resemblance. Or, it can resemble effortless intelligence. Even though crows often symbolize death and menace, they are also known for their incredible intelligence as well. The emphasis would then be creativity and rationale.
As for the composition of the piece, you did a good job in achieving balance with the starkly contrasting black and white. But you also took care to add a bit of tint which softens the picture. It is visually appealing and the silhouettes draw a curious eye in. You took care to structure the precision in the facial anatomy. I feel it might have been better if you echoed this precision in the neck and shoulders. At least the neck seems kind of long, unless you desired that she might be a tree?
I think it would be interesting if you incorporated the birds with the hair a little bit more. I see you have done that with the leg of one of the crows, and I have noticed the unity it has achieved. The crow on her shoulder does allow balance of the picture, but he does seem a bit misplaced. I would have drawn him in flight as well. However, it does add a slightly humerus touch to it.
A meditative state and watercolor hair made of ominous winged creatures. The dark mood of crows compliments and contrasts the purity of so much light which keeps this moment of serenity real. Lovely work.