Birds and Ornithology.
Feathers and Feather Tracts.
Anatomy and Physiology.
External Structural Characters.
Plumages and Plumage Coloration.
Nests and Nest-Building.
Eggs, Egg-Laying, and Incubation.
Young and Their Development.
Longevity, Numbers, and Populations.
Ancestry, Evolution, and Decrease of Birds.