In aquatic flightless birds (penguins), wings can serve as flippers.
[1] Like most other tetrapods, the forelimb of birds consists of the shoulder (with the humerus), the forearm (with the ulna and the radius), and the hand.
Different shapes correspond to different trade-offs between advantages such as speed, low energy use, and maneuverability.
This type of wing allows for tight maneuvering in confined spaces such as dense vegetation.
They are also common in species that use a rapid takeoff to evade predators, such as pheasants and partridges.
This may take the form of almost hovering (as used by kestrels, terns and nightjars) or in soaring and gliding flight, particularly the dynamic soaring used by seabirds, which takes advantage of wind speed variation at different altitudes (wind shear) above ocean waves to provide lift.
These wings are favored by larger species of inland birds, such as eagles, vultures, pelicans, and storks.