<Ul> <Li> Birds by population <Ul> <Li> Anseriformes (waterfowl) </Li> <Li> Apodiformes (swifts and hummingbirds) </Li> <Li> Caprimulgiformes (nightjars and relatives) </Li> <Li> Charadriiformes (gulls and relatives) </Li> <Li> Ciconiiformes (storks and relatives) </Li> <Li> Columbiformes (doves and pigeons) </Li> <Li> Coraciiformes (kingfishers and relatives) </Li> <Li> Cuculiformes (cuckoos and relatives) </Li> <Li> Falconiformes (falcons and relatives) </Li> <Li> Galliformes (gamebirds) </Li> <Li> Gaviiformes (loons or divers) </Li> <Li> Gruiformes (cranes and relatives) </Li> <Li> Passeriformes (perching birds) </Li> <Li> Pelecaniformes (pelicans and relatives) </Li> <Li> Phoenicopteriformes (flamingos) </Li> <Li> Piciformes (woodpeckers and relatives) </Li> <Li> Podicipediformes (grebes) </Li> <Li> Procellariiformes (albatrosses and petrels) </Li> <Li> Psittaciformes (parrots) </Li> <Li> Sphenisciformes (penguins) </Li> <Li> Strigiformes (owls) </Li> <Li> Struthioniformes (ratites) </Li> <Li> Tinamiformes (tinamous) </Li> <Li> Trogoniformes (trogons and quetzals) </Li> </Ul> </Li> </Ul> <Li> Birds by population <Ul> <Li> Anseriformes (waterfowl) </Li> <Li> Apodiformes (swifts and hummingbirds) </Li> <Li> Caprimulgiformes (nightjars and relatives) </Li> <Li> Charadriiformes (gulls and relatives) </Li> <Li> Ciconiiformes (storks and relatives) </Li> <Li> Columbiformes (doves and pigeons) </Li> <Li> Coraciiformes (kingfishers and relatives) </Li> <Li> Cuculiformes (cuckoos and relatives) </Li> <Li> Falconiformes (falcons and relatives) </Li> <Li> Galliformes (gamebirds) </Li> <Li> Gaviiformes (loons or divers) </Li> <Li> Gruiformes (cranes and relatives) </Li> <Li> Passeriformes (perching birds) </Li> <Li> Pelecaniformes (pelicans and relatives) </Li> <Li> Phoenicopteriformes (flamingos) </Li> <Li> Piciformes (woodpeckers and relatives) </Li> <Li> Podicipediformes (grebes) </Li> <Li> Procellariiformes (albatrosses and petrels) </Li> <Li> Psittaciformes (parrots) </Li> <Li> Sphenisciformes (penguins) </Li> <Li> Strigiformes (owls) </Li> <Li> Struthioniformes (ratites) </Li> <Li> Tinamiformes (tinamous) </Li> <Li> Trogoniformes (trogons and quetzals) </Li> </Ul> </Li> <Ul> <Li> Anseriformes (waterfowl) </Li> <Li> Apodiformes (swifts and hummingbirds) </Li> <Li> Caprimulgiformes (nightjars and relatives) </Li> <Li> Charadriiformes (gulls and relatives) </Li> <Li> Ciconiiformes (storks and relatives) </Li> <Li> Columbiformes (doves and pigeons) </Li> <Li> Coraciiformes (kingfishers and relatives) </Li> <Li> Cuculiformes (cuckoos and relatives) </Li> <Li> Falconiformes (falcons and relatives) </Li> <Li> Galliformes (gamebirds) </Li> <Li> Gaviiformes (loons or divers) </Li> <Li> Gruiformes (cranes and relatives) </Li> <Li> Passeriformes (perching birds) </Li> <Li> Pelecaniformes (pelicans and relatives) </Li> <Li> Phoenicopteriformes (flamingos) </Li> <Li> Piciformes (woodpeckers and relatives) </Li> <Li> Podicipediformes (grebes) </Li> <Li> Procellariiformes (albatrosses and petrels) </Li> <Li> Psittaciformes (parrots) </Li> <Li> Sphenisciformes (penguins) </Li> <Li> Strigiformes (owls) </Li> <Li> Struthioniformes (ratites) </Li> <Li> Tinamiformes (tinamous) </Li> <Li> Trogoniformes (trogons and quetzals) </Li> </Ul> <Li> Anseriformes (waterfowl) </Li>

What is the most populated species in the world