1. Ostriches: The largest living bird, ostriches are flightless birds that are found in Africa. They have long legs that they use for running, and can reach speeds of up to 70 km/h. Ostriches' wings are primarily used for balance and during mating rituals.
2. Penguins: Penguins are flightless birds that live in the Southern Hemisphere. They are highly adapted to life in water, and have streamlined bodies, flippers, and thick layers of fat for insulation. Penguins use their wings for swimming and diving rather than for flying.
3. Cassowaries: Cassowaries are large, flightless birds found in the rainforests of New Guinea and Australia. They have heavy bodies and strong legs with three sharp claws on each foot. Cassowaries use their wings for balance and during courtship displays.
4. Kiwis: Kiwis are small, flightless birds native to New Zealand. They have long, thin beaks and are well-adapted to living in burrows. Kiwis use their wings for balance and for digging.
5. Moa: Moa were large, flightless birds that were found in New Zealand until the 18th century when they were hunted to extinction. They had small wings that were not suitable for flying.
6. Dodo: Dodo birds were flightless birds native to the island of Mauritius in the Indian Ocean. They were hunted to extinction in the 17th century due to habitat destruction and predation by introduced species.