The term 'Flightless Big Bird' refers to the EMU, a large, flightless bird native to Australia. The EMU is the second-largest living bird by height, after the Ostrich. It is a swift-running, powerful bird with long legs and can reach speeds of up to 50 km/h. The EMU is also notable for its ability to swim and dive. It is an important cultural icon of Australia and is featured on the Australian Coat of Arms.