The term 'Big Aussie Birds' refers to two of the largest birds native to Australia, the Emu and the Cassowary. The Emu is the second-largest living bird in the world by height, after the Ostrich. It is a flightless bird with long legs and a long neck, and can reach up to 2 meters in height. The Cassowary is the third-largest living bird in the world, and is native to tropical rainforests of northern Australia and New Guinea. It is a large, flightless bird with a distinctive bright blue neck and head, and can reach up to 1.5 meters in height. Both the Emu and the Cassowary are iconic symbols of Australia, and are protected under Australian law.