There are three things to catch in your first fast sketch. The posture, proportions, and angles. Start with the simple shapes first and build from there. In a circling hawk you may be able to build a compound picture from several different views. If you only get a quick look, do the best you can. I can only hold an image in my memory for a few seconds before needing to refresh with the real bird. You may get an angle of a wing, proportions of a tail or some other detail. You do not have to draw the whole bird if you do not remember what you saw. Drawing hawks in flight is a great way to train yourself to look more carefully at the birds you see.
Click on the first image to start the step by step slide show.
This bird was flying horizontally to my line of site. The first line is through the axis of the body.
I now add lines to indicate the length and angles of the wings. The farther wing is foreshortened.
I rough in the shape of the body with a long oval. I am not worried about details, just the size of the body relative to the wings.
I block in the approximate depth of the wings. At this stage it helps just to think of the wing as a big plank.
Block in the break between the outer primary feathers and the inner secondaries.
From the wrist carve in the angle of the leading edge of the primary feathers.
Chisel in the angles of the body. Many raptors have a chesty look.
All the details hang on the framework you have made. If you can not see any details, stick with a silhouette.