The Emu (pronunciation: IPA: /ˈiːm.juː/[1][2]), Dromaius novaehollandiae, is the largest bird native to Australia and the only extant member of the genusDromaius. It is also the second-largest extant bird in the world by height, after its ratite relative, the ostrich. The soft-feathered, brown, flightless birds reach up to 2 m (6 ft) in height. The Emu is common over most of mainland Australia, although it avoids heavily populated areas, dense forest and arid areas. Emus can travel great distances at a fast, economical trot and, if necessary, can sprint at 50 km/h (30 mph) for some distance at a time.[3] They are opportunistically nomadic and may travel long distances to find food; they feed on a variety of plants and insects.
Kangaroo Island Emu (Dromaius baudinianus) is an extinctbird, a member of the family Casuariidae. It was restricted to Kangaroo Island, South Australia. It differed from the mainland Emu mainly in its smaller size. The species became extinct in approximately 1827 (Stattersfield et al. 1998).
The Ostrich (Struthio camelus) is a flightless bird native to Africa. It is the only living species of its family, Struthionidae, and its genus, Struthio. It is distinctive in its appearance, with a long neck and legs and the ability to run at speeds of about 65 km/h (40 mph), the top landspeed of any bird.[1]
The Southern Cassowary, Casuarius casuarius, also known as Double-wattled Cassowary or Two-wattled Cassowary, is a large flightless black bird with hard and stiff plumage, a brown casque, blue face and neck, red nape and two red wattles hanging down its throat. The three-toed feet are thick and powerful, equipped with a lethal dagger-like claw on the inner toe. The plumage is sexually monomorphic, but the female is dominant and larger with a longer casque and brighter-colored bare parts. The immature bird has plain brown plumage.
Birds of Australia 
not too much longer now :)