Guillemots are so hard to draw! Their shape is often fugitive - a soft, chocolate brown smoothness hiding the angles of their wings. This is made more complex by the way in which they bunch together on cliff edges during the breeding season. Sometimes when you draw them it is almost impossible to tell where one bird ends and another begins! I was trying to capture some of that in this drawing - how the birds form a shape as a whole, and also how that form merges into the monochrome cliff-edge colours.