I used to think that the trick to drawing bird feathers was to draw the feathers. How hard can that be? I spent hours studying feather tracts and the way that feathers overlap. I would then try to show everything I had learned, feather by feather. I often found myself frustrated by photographs and even study skins or taxidermy birds in which I could not discern the way the feathers overlapped. In spite of rigorous research, my birds felt stiff, diagrammatic, and didn’t look like the birds I saw in the field. I was missing one critical step. Yes, studying the plumage, feather tracts, and wings is important. Once you understand this structure, the trick is to suggest that detail and complexity instead of drawing every feather. Put another way, understand more than you see, and draw less than you know.
If you can’t see it, don’t draw it. Should you find yourself frustrated that you can’t see some aspect of the feather detail, just leave it out. If you can’t see it, adding these details to your drawing will turn your sketch into a wing anatomy diagram rather than a drawing of the bird. This seems obvious to me now but it has taken me years to learn this lesson. The best drawings are the ones that give you a suggestion of detail and the underlying structure without noodleing in every feature.
Compare these two drawings of House Wrens. Which do you like better? Why? Click image to enlarge.
You can suggest the wing in many ways. Choose a level of detail that is right to the level of detail you really see. On a distant bird you might show less. On a close cooperative bird (and a more detailed drawing overall) you might show more. Here are some examples of how you might simplify a wing. These are not a step-by-step tutorial leading to a detailed drawing but different possibilities of how you might simplify a wing. Click the first image to enlarge and start the slide show.
So here is your homework. Learn the wing and primary feather groups. Practice drawing them feather by feather as an exercise. Then give up what you know and simplify your understanding to key lines. Be playful with it. What is the most you can show with the least amount of fuss.