 It has also been reported in goshawks, bustard chicks, and psittacine birds (budgerigars, macaws, and conures).The syndrome is acquired in young birds.Due to a high-calorie diet, especially one high in proteins and/or low in vitamin D, vitamin E, and manganese, one or both carpus (wrist) joints are retarded in their development relative to the rest of the wing; for reasons unknown, if only one wing is affected, it is usually the left one.