Sources: New Oxford American Dictionary; Wikipedia
Ornithology: the scientific study of birds. From the late 17th century from modern Latin ornithologia, from Greek ornithologos ‘treating of birds’.
Birds: are a group of warm-blooded vertebrates constituting the class Aves, characterized by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight skeleton.
Paleontology: the branch of science concerned with fossil animals and plants. From mid 19th century: from paleo- + Greek onta ‘beings’ (neuter plural of ōn, present participle of einai ‘be’) + -logy.
Phylogeny: the branch of biology that studies the evolutionary development and diversification of a species or group of organisms, or of a particular feature of an organism. From the late 19th century from Greek phulon, phulē ‘race, tribe’+ -geny – ‘birth’.
Taxonomy: the identification, naming and classification of organisms. From the early 19th century: coined in French from Greek taxis ‘arrangement’ + -nomia ‘distribution’.
Ontogeny: the branch of biology that studies the development of an individual organism or anatomical or behavioral feature from the earliest stage to maturity. From the late 19th century from Greek ōn, ont- ‘being’+ -geny – ‘birth’.
Anatomy: the branch of science concerned with the bodily structure of humans, animals, and other living organisms. From the late Middle English: from Old French anatomie or late Latin anatomia, from Greek, from ana- ‘up’ + tomia ‘cutting’ (from temnein ‘to cut’).
Physiology: the branch of biology that deals with the normal functions of living organisms and their parts. From the early 17th century: from Latin physiologia (perhaps via French), from Greek phusiologia ‘natural philosophy’.
Passerine: is any bird of the order Passeriformes (Latin passer (“sparrow”) + formis (“-shaped”)), which includes more than half of all bird species. Sometimes known as perching birds or songbirds, passerines are distinguished from other orders of birds by the arrangement of their toes (three pointing forward and one back), which facilitates perching.