Bird Orders and Groups

• Buttonquail
• Cranes, Coots and Rails
• Cuckoos, Roadrunners, and Anis
• Doves and Pigeons
• Ducks, Geese and Swans
• Falcons and Raptors
• Game Birds
• Kingfishers, Bee-Eaters, Hoopoe and Rollers
• Mousebirds
• Nightjars, Frogmouths and Oilbirds
• Ostriches, Emus and Cassowaries
• Owls

• Pelicans, Cormorants, Gannets
• Penguins
• Perching Birds
• Ratites@
• Storks and Long-legged Waders
• Swifts and Hummingbirds
• Tinamous
• Trogons and Quetzals
• Waders, Gulls and Auks
• Waterfowl@
• Woodpeckers, Barbets and Toucans

• Science: Biology: Plants and Animals: Animalia: Chordata: Aves 

• Audubon Guides: Bird Families  - Comprehensive guide to bird families and groups with an introduction to each family, numbers of species worldwide and in North America, identification, and characteristics.
• BirdLife International: Taxonomy  - Global partnership of conservation organisations for birds and their habitats explains the rationale behind the taxonomy of their checklist of endangered species. Includes information on the working group, sources, sequences, and taxa under review.