many species of birds are eaten by humans. domesticated and undomesticated birds are sources of eggs, meat, and feathers. in english, domesticated birds are often called poultry, undomesticated birds are called game. songbirds, parrots and other species are popular as pets. guano, which is bird manure, is harvested for use as a fertiliser. birds figure throughout human culture. about 120–130 species have become extinct due to human activity since the 17th century and hundreds more before then. human activity threatens about 1,200 bird species with extinction, though efforts are underway to protect them. recreational bird-watching is an important part of the ecotourism industry.