Key to Aves
- Phoenicopteridae: Large light pink to scarlet web-footed wading bird; Bill bent downward; Birds of brackish lakes. Flamingos.
- 2: Feet lobed or unlobed; small to large birds of various colors.
- 3: Legs are small; Feet covered with bare skin; Long wings, but short and stout humerus bones.
- 4: Legs small to large; Feet covered with scales called scutes.
- Trochilidae: Beak long and thin; Wings flap very rapidly, allowing it to hover; Generally feed on nectar. Hummingbirds.
- 5: Beak short; Does not generally flap wings very rapidly; Usually insectivorous.
- 6: Nocturnal and carnivorous, feeding mostly on insects and small rodents; generally fly almost silently; Feathers have few radiates and longer pennulum; Large, tubular shaped eyes unable to move; Ear placement asymmetrical. Owls.
- 7: Nocturnal or diurnal with various feeding habits; Generally make noise during flight; Small, round eyes.
- Apodidae: Not able to perch; Tail not deeply forked; Crest not present on head. Swifts.
- Hemiprocnidae: Able to perch; Tail deeply forked; Crest present on head. Treeswifts.
- Strigidae: Inner toe shorter than third toe, which has a smooth edge; Circular facial disk; Four notches present in sternum which is not fused to the furcula. True owls.
- Tytonidae: Inner toe is the same size as other toes and has a pectinate claw; Heart-shaped facial disk; Two notches present in sternum which is fused to the furcula. Barn owls.
- 8: Strong, curved bill; Two clawed toes face forward and two clawed toes face backward; Generally vividly multi-colored and eat seeds, nuts, fruit, buds, or other plant material.
- 9: Various bill shapes, but generally not strongly curved downward; Various dactyly, but generally not two claws forward and two backward.
- Cacatuoidea (cockatoos), 21 species
- Psittacoidea (true parrots), 330 species
- Strigopoidea (New Zealand parrots), 9 species (excluding Kakapo- flightless)
- 10: Sharply hooked beak with a cere on the proximodorsal surface; Strong legs with talons, including an opposable hind claw; Generally carnivorous and relatively long-lived. Raptors
- 11: Beaks of various sizes, but generally don't have a cere (few exceptions including turkeys, skuas, and curassows).
- Accipitridae (eagles, hawks, old world vultures)
- Pandion haliaetus (Osprey), 1 species
- Falconidae (Falcons & caracaras), ~60 species
- Sagittariius serpentarius (Secretarybird), 1 species
- Cathartidae (New World vulture), 7 species
- 12: Tubular nasal passage present, capable of smelling; Majority of food comes from the open ocean; Bill made up of seven to nine horny plates. Tubenoses.
- 13: Tubular nasal passage absent; Majority of food terrestrial or of smaller bodies of water; Bill not made up of horny plates.
- Diomedeidae (albatrosses), 21 species (debated)
- Hydrobatidae (storm petrels), 7 species
- Pelecanoididae (diving petrels), 4 species
- Procellariidae, ~70 species
- Opisthocomus hoazin: spiky reddish-brown crest present on head; Unfeathered blue face and red eyes; Manure-like odor.
- 14: Crest absent or if present, not spiky and reddish-brown.
- Podicipedidae: Plumage is dense and waterproof; the underside the feathers are at right-angles to the skin, sticking straight out to begin with and curling at the tip. Grebes.
- 15: Plumage may or may not be waterproof, but if it is, feathers not at right angles to skin.