The long angled line running from the tail to the base of the neck on the right edge is the “defining line”. A stroke like this helps me decide the general length and angle of the bird’s stance, its motion, and in many ways the essence of the bird. As the drawing progresses, you may notice how this defining line serves to anchor the rest of the drawing, even if only loosely. It’s very strange how often that first single line, that one quick stroke, just doesn’t work. So often it is erased, and redrawn before anything else… Included are boundaries for primaries, two groups of coverts (greater and median), and a hint of the tertials. The saddle of the back is roughly marked, but for me personally, it is the first few dark areas on the head and face that really “open the gate” for the rest of the drawing.