The wing is one of the most remarkable parts of a bird. When extended in flight, it serves as a lightweight and efficient airfoil. But when birds are at rest, they fold their wings and hold them tight against the sides of their bodies. The two positions look entirely different. Learning just a few key points will help you understand and reconcile the varying shapes and patterns.
The wings of all birds share the same basic structure, consisting of flight feathers and wing coverts.