The United States Fish and Wildlife Service has its origin in the work of C. Hart Merriam and the old Bureau of Biological Survey in the United States Department of Agriculture. By 1885, the ornithological work being conducted by the American Ornithologists' Union (AOU) and other private organizations and individuals had grown to the point where private interests were no longer able to finance it sufficiently. Congress was then persuaded to establish a section of ornithology in the Division of Entomology of the Department of Agriculture. The purpose of the section was "the promotion of economic ornithology, or the study of the interrelation of birds and agriculture, an investigation of the food, habits, and migration of birds in relation to both insects and plants, and publishing reports thereon." Through the influence of the AOU and Spencer F. Baird of the Smithsonian Institution, Merriam was appointed Ornithologist. The following year the section attained independent rank as the Division of Ornithology. In 1888 its responsibilities were expanded to include mammals, resulting in a new title - the Division of Economic Ornithology and Mammalogy.
Merriam's concept of life zones which are fitted by nature for the life of certain associations of plants and animals, and his estimation of the value which the delimitation of such areas would have for agriculture, led him to propose the establishment of a Biological Survey into which his own division would be merged. The 1896 name change of the Division to the Division of Biological Survey was the result. In 1905, it became a Bureau within the Department of Agriculture.
The Bureau of Biological Survey remained within the Department of Agriculture until 1939 when it was transferred to the Department of Interior. The following year it was combined with the Bureau of Fisheries, which had been transferred to Interior from the Department of Commerce, to form the United States Fish and Wildlife Service.
From the beginning of the Survey's work, field research was of primary importance in gathering information concerning the interrelation of birds, mammals, and agriculture. Field surveys continued to play an important role as the Bureau's work evolved to include game protection, research on fur-bearing animals, the management of game refuges, predatory animal control, and the protection of migratory birds. Surveys conducted by the Bureau usually entailed sending individual naturalists or groups of workers to collect mammals, birds, reptiles, and amphibians in a particular state or geographic region. The collections would be augmented by detailed notes, specimens of representative plant life, and photographs of the environment being studied. The compiled materials would serve as the basis for a detailed report on the region. Biological surveys were also conducted at several regional field stations administered by the Bureau.