The common ostrich, also known as Struthio camelus, is the largest and heaviest bird on Earth, reaching 2.7 meters tall and weighing up to 130 kg.

The Somali Ostrich, a unique species of the blue-necked ostrich, stands as the second-largest bird globally, boasting impressive running capabilities and a height of up to 2.7 meters.

The southern cassowary, a slightly larger species, can reach a maximum weight of 58kg and is found in New Guinea and Queensland, Australia.

Casuarius unappendiculatus, a flightless Northern Cassowary, is found in New Guinea, weighing 58kg and incubated by a male for nine months after being laid by a female.

The emu, a member of the Casuariidae family, can reach a maximum weight of 55kg and stands 190cm tall, with average weights ranging between 30 and 45kg.

Emperor Penguin, a 115cm tall, 46kg species, can reach a breeding colony in Antarctica by trekking 120km over ice.

Greater Rhea americana, an omnivorous grassland species, can weigh over 25kg and is found in Argentina, Bolivia, Brazil, Paraguay, and Uruguay.

Dwarf Cassowary, smallest species, lives in New Guinea forests, feeding on fungi, fruit, insects, and small animals, reaching 17.6kg.

Mute swan, a vocal bird with a maximum weight of 22.5kg, is found in Central and Northern Europe and Central and Eastern Asia.

Darwin's rhea, also known as rhea pennata, is a lesser rhea found in Argentina, Bolivia, Chile, and Peru, with a maximum weight of 25kg.