The crossword solution for the term 'Bird Part' is TAIL, which is a four letter word. The TAIL of a bird is an important part of its anatomy, as it helps to provide balance and stability while in flight. It also serves as a rudder, allowing the bird to make quick turns and changes in direction. The TAIL feathers are often brightly colored and can be used for display purposes, such as courtship or territorial displays. The TAIL can also be used to communicate with other birds, as some species have specialized TAIL feathers that can be used to send signals.