Australian Pied budgerigar mutation spot, clear areas on the wings and a clear area on the breast. They differ from the Clearflight Pied in the nape spot, which is not always present, and in their feet, which are usually pink. But the main point of difference is in the clear area of the body, which in the Australian Pied is located in the middle or lower breast, with the upper breast being always normally coloured, so that there is a clear division between the mask and the breast, just as in normal birds. In the Clearflight Pied the clear area on the breast, if
Supernumerary body part considered to have lost much or all of their original function through evolution. These body parts can be classed as additional to the required functioning of the body. In human anatomy the vermiform appendix is sometimes classed as a vestigial remnant. Prosthesis is an artificial extension that replaces a body part, and cybernetics is the study of computer technology in relation to organisms which can include replacement or additional body parts. Body integrity identity disorder (BIID) is a psychiatric disorder in which a person thinks that they have one or more additional limbs than they should, despite having two arms