Birds and humans

Birds are an important food source for humans. The most commonly eaten species is the domestic chicken and its eggs, although geese, pheasants, turkeys, and ducks are also widely eaten. Other birds that have been utilized for food include emus, ostriches, pigeons, grouse, quails, doves, woodcocks, songbirds, and others, including small passerines such as finches. Birds grown for human consumption are referred to as poultry.

At one time swans and flamingos were delicacies of the rich and powerful, although these are generally protected now.

Besides meat and eggs, birds provide other items useful to humans, including feathers for bedding and decoration, guano-derived phosphorus and nitrogen used in fertilizer and gunpowder, and the central ingredient of bird's nest soup.

Humans have caused the disappearance of some bird species. The Passenger Pigeons were hunted to extinction, even being the world's most common bird at one time, and Dodos, which lay their eggs on the ground, became extinct when humans brought pigs to their habitat which escaped and ate the dodo eggs[citation needed], and when humans easily hunted them because of the dodos' lack of fear for humans. Many others have become endangered or extinct through habitat destruction (e.g. by deforestation or intensive agriculture).

Some species have come to depend on human activities for food and are widespread to the point of being pests. For example, the common pigeon or Rock Pigeon (Columba livia) thrives in urban areas around the world. In North America, introduced House Sparrows, European Starlings, and House Finches are similarly widespread.

Other birds have long been used by humans to perform tasks. For example, homing pigeons were used to carry messages before the advent of modern instant communications methods (many are still kept for sport). Falcons are still used for hunting, while cormorants are employed by fishermen. Chickens and pigeons are popular as experimental subjects, and are often used in biology and comparative psychology research. As birds are very sensitive to toxins, the Canary was used in coal mines to indicate the presence of poisonous gases, allowing miners sufficient time to escape without injury.

Colorful, particularly tropical, birds (e.g. parrots, and mynas) are often kept as pets although this practice has led to the illegal trafficking of some endangered species; CITES, an international agreement adopted in 1963, has considerably reduced trafficking in the bird species it protects.

Bird diseases that can be contracted by humans include psittacosis, salmonellosis, campylobacteriosis, Newcastle's disease, mycobacteriosis (avian tuberculosis), avian influenza, giardiasis, and cryptosporidiosis.