Relationship with humans
Since birds are highly visible and common animals, humans have had a relationship with them since the dawn of man.[168] Sometimes, these relationships are mutualistic, like the cooperative honey-gathering among honeyguides and African peoples such as the Borana.[169] Other times, they may be commensal, as when species such as the House Sparrow[170] have benefited from human activities. Several bird species have become commercially significant agricultural pests,[171] and some pose an aviation hazard.[172] Human activities can also be detrimental, and have threatened numerous bird species with extinction (hunting, avian lead poisoning, pesticides, roadkill, and predation by pet cats and dogs are common sources of death for birds).
Birds can act as vectors for spreading diseases such as psittacosis, salmonellosis, campylobacteriosis, mycobacteriosis (avian tuberculosis), avian influenza (bird flu), giardiasis, and cryptosporidiosis over long distances. Some of these are zoonotic diseases that can also be transmitted to humans.[173]
Economic importance

Domesticated birds raised for meat and eggs, called poultry, are the largest source of animal protein eaten by humans; in 2003, 76 million tons of poultry and 61 million tons of eggs were produced worldwide.[174] Chickens account for much of human poultry consumption, though turkeys, ducks, and geese are also relatively common. Many species of birds are also hunted for meat. Bird hunting is primarily a recreational activity except in extremely undeveloped areas. The most important birds hunted in North and South America are waterfowl; other widely hunted birds include pheasants, wild turkeys, quail, doves, partridge, grouse, snipe, and woodcock.[175] Muttonbirding is also popular in Australia and New Zealand.[176] Though some hunting, such as that of muttonbirds, may be sustainable, hunting has led to the extinction or endangerment of dozens of species.[177]

The use of cormorants by Asian fishermen is in steep decline but survives in some areas as a tourist attraction.Other commercially valuable products from birds include feathers (especially the down of geese and ducks), which are used as insulation in clothing and bedding, and seabird feces (guano), which is a valuable source of phosphorus and nitrogen. The War of the Pacific, sometimes called the Guano War, was fought in part over the control of guano deposits.[178]

Birds have been domesticated by humans both as pets and for practical purposes. Colourful birds, such as parrots and mynas, are bred in captivity or kept as pets, a practice that has led to the illegal trafficking of some endangered species.[179] Falcons and cormorants have long been used for hunting and fishing, respectively. Messenger pigeons, used since at least 1 AD, remained important as recently as World War II. Today, such activities are more common either as hobbies, for entertainment and tourism,[180] or for sports such as pigeon racing.

Amateur bird enthusiasts (called birdwatchers, twitchers or, more commonly, birders) number in the millions.[181] Many homeowners erect bird feeders near their homes to attract various species. Bird feeding has grown into a multimillion dollar industry; for example, an estimated 75% of households in Britain provide food for birds at some point during the winter.[182]
Religion, folklore and culture

Birds play prominent and diverse roles in folklore, religion, and popular culture. In religion, birds may serve as either messengers or priests and leaders for a deity, such as in the Cult of Makemake, in which the Tangata manu of Easter Island served as chiefs,[183] or as attendants, as in the case of Hugin and Munin, two Common Ravens who whispered news into the ears of the Norse god Odin.[184] Priests were involved in augury, or interpreting the words of birds while the "auspex" (from which the word "auspicious" is derived) watched their activities to foretell events.[185] They may also serve as religious symbols, as when Jonah (Hebrew: יוֹנָה, dove) embodied the fright, passivity, mourning, and beauty traditionally associated with doves.[186] Birds have themselves been deified, as in the case of the Common Peacock, which is perceived as Mother Earth by the Dravidians of India.[187] Some birds have also been perceived as monsters, including the mythological Roc and the Māori's legendary Pouākai, a giant bird capable of snatching humans.[188]
Birds have been featured in culture and art since prehistoric times, when they were represented in early cave paintings.[189] Birds were later used in religious or symbolic art and design, such as the magnificent Peacock Throne of the Mughal and Persian emperors.[190] With the advent of scientific interest in birds, many paintings of birds were commissioned for books. Among the most famous of these bird artists was John James Audubon, whose paintings of North American birds were a great commercial success in Europe and who later lent his name to the National Audubon Society.[191] Birds are also important figures in poetry; for example, Homer incorporated Nightingales into his Odyssey, and Catullus used a sparrow as an erotic symbol in his Catullus 2.[192] The relationship between an albatross and a sailor is the central theme of Samuel Taylor Coleridge's The Rime of the Ancient Mariner, which led to the use of the term as a metaphor for a 'burden'.[193] Other English metaphors derive from birds; vulture funds and vulture investors, for instance, take their name from the scavenging vulture.[194]
Perceptions of various bird species often vary across cultures. Owls are associated with bad luck, witchcraft, and death in parts of Africa,[195] but are regarded as wise across much of Europe.[196] Hoopoes were considered sacred in Ancient Egypt and symbols of virtue in Persia, but were thought of as thieves across much of Europe and harbingers of war in Scandinavia.[197]
Conservation

.Main article: Bird conservation
See also: Late Quaternary prehistoric birds, List of extinct birds, and Raptor conservation
Though human activities have allowed the expansion of a few species, such as the Barn Swallow and European Starling, they have caused population decreases or extinction in many other species. Over a hundred bird species have gone extinct in historical times,[198] although the most dramatic human-caused avian extinctions, eradicating an estimated 750–1800 species, occurred during the human colonisation of Melanesian, Polynesian, and Micronesian islands.[199] Many bird populations are declining worldwide, with 1,227 species listed as threatened by Birdlife International and the IUCN in 2009.[200][201]

The most commonly cited human threat to birds is habitat loss.[202] Other threats include overhunting, accidental mortality due to structural collisions or long-line fishing bycatch,[203] pollution (including oil spills and pesticide use),[204] competition and predation from nonnative invasive species,[205] and climate change.

Governments and conservation groups work to protect birds, either by passing laws that preserve and restore bird habitat or by establishing captive populations for reintroductions. Such projects have produced some successes; one study estimated that conservation efforts saved 16 species of bird that would otherwise have gone extinct between 1994 and 2004, including the California Condor and Norfolk Parakeet.[206]