The extinct 'WONDERLAND' bird is known as the DODO, which is a four-letter word. The DODO was a large, flightless bird that lived on the island of Mauritius in the Indian Ocean. It was first discovered by Portuguese sailors in the 16th century and became extinct in the late 17th century due to human activity. The DODO has become an iconic symbol of extinction, and its name has been used in various works of literature, such as Lewis Carroll's Alice's Adventures in WONDERLAND.