A general analysis of bird biology and its classification was presented in The Elements of Ornithology. The book is among the seven series of First Books of Natural History in preparation for its use in schools and colleges. Its main topic is the introduction to Ornithology. Ornithology is a field of zoology that details the study of birds. Ornithology is derived from the ancient Greek word, ornithologos, that means rationale or explanation and from the Latin word ornithologia meaning bird science. The study of birds has a lengthy history and advanced into numerous key concepts in evolution, behaviour and ecology similar to the definition of species, the method of speciation, instinct, learning, ecological niches, guilds, island biogeography, phylogeography and conservation. The origin of ornithology emulates the origin of biology, as well as other scientific studies, ecology, anatomy, physiology, paleontology, and currently molecular biology. The scientific studies move from descriptions to the application of patterns, and elaborating on the methods that outgrowth the patterns. In prehistorical times, humans have had an inter relationship with birds with stone age sketches being the oldest specifications of interest in birds. Birds, then, were necessary as a source of food. Excavations of bones were found in the early Stone Age such as the Waterbird and seabird, found in shell mounds on the island Oronsay off the coast of Scotland. In the Victorian era, the bird collectors studied the differences of bird forms and habits all throughout the geographic regions. The study of the different variations in geographical regions begun the presentation of trinomial names.