Flutes come in many varieties that produce sound through the vibration of air inside them. This includes the Western concert flute as well as traditional flutes from various cultures around the world. Specific types of flutes discussed include the bird whistle, which mimics bird sounds, the nose flute played in parts of Asia and the Pacific, and the alto flute, which is sometimes called a bass flute for historical reasons despite being a different instrument than the true bass flute.