Angel wing, also known as airplane wing,[1] slipped wing, crooked wing, and drooped wing,[citation needed] is a syndrome that affects primarily aquatic birds, such as geese and ducks, in which the last joint of the wing is twisted with the wing feathers pointing out laterally, instead of lying against the body. Males develop it more frequently than females. It has also been reported in goshawks, bustard chicks, and psittacine birds (budgerigars, macaws, and conures).[2]