Having transferred the drawing onto a piece of double thick illustration board (via projector), I fine tuned it, sealed the board with acrylic matte medium and got to work.
I spent a full day painting and when I was done I had a problem: a major color (the bricks) were competing with and drowning out my other elements. I had painted the bricks to be warm, like the setting sun was illuminating them. The birds were supposed to jump out but instead they could not compete with the bright wall. So I scanned the image and tried some possible solutions in Photoshop. Below are the two options I settled on.
The answer was to go with the first option and so early the next morning, hours before I had to leave for the SCBWI retreat with my finished piece in hand, I began to make the necessary changes.