People who start out drawing (instead of painting), like I did, may end up only seeing line, not shape. It took me quite awhile to not only see shapes first, but to think that way. When you go out to sketch in nature, it can be overwhelming. So much to choose from, often limited time. Seeing the big shapes in a scene or animal instead of individual bits can help you more quickly start to sort out what you want to focus on.
This first example is an easy one…sky, trees, ground. Three “shapes”. The second image, created in Pixelmator Pro, shows how I chose to divide them. Notice that I’m not seeing individual trees, but the shape that the whole row of them makes. Within that I can move them around, change the size relationships, whatever I want. But the important abstract concept is seeing all the trees as one long shape.
Birds don’t stay still for long, so getting the simplest shapes down fast is critical. Don’t worry about eyes or markings. When sketching birds (or other animals) go for the overall impression. Then fill in, if you want to, markings and shadow areas from further observation and/or visual memory. Leave parts like the branch (or trees or grass, etc), which isn’t going to move, for the end. Don’t get caught up in detail. Often less is more.