The potential of insectivorous birds and other wild vertebrates as regulators of pest insect populations has long been recognized. Laws to protect beneficial birds were proposed as early as 1877 by the United States Entomological Commission (1878). Study of the relationships of birds to man was called economic ornithology and included beneficial and harmful aspects. Before the development of synthetic chemical pesticides, birds were considered to be significant predators of agricultural insect pests by many farmers, and were encouraged for pest control. There was great interest in determining the kinds and amounts of insects eaten by birds. Much of the research involved examination of stomach contents (food habits analysis). It is noteworthy that S.A. Forbes, considered the founder of economic ornithology (McAtee 1933), was also a leading entomologist who defined many of the principles of integrated pest management (IPM) more than 100 years ago (Metcalf 1980).