Other forms of pollution, such as acid rain and oil spills, cause prey populations to decline, and in turn cause the decline of diurnal birds of prey populations. Discarded trash, like used monofilament line, can entangle and harm individual diurnal birds of prey. Diurnal birds of prey may be deliberately or accidentally poisoned. Though direct poisoning is illegal in the United States, it's still practiced in other areas of the world. Accidental poisoning occurs when diurnal birds of prey eat rodents or seed-eating birds that have been poisoned by farmers for pest control.
Lead poisoning occurs when diurnal birds of prey eat carcasses or live prey shot with lead bullets.
In the U.S., there's been a gradual elimination of lead from shotgun shells since the mid-1980s. Some carcasses are set deliberately for diurnal birds of prey. Falconry is the sport of taking wild game by means of a trained bird of prey, usually a hawk or falcon. Falconry dates back to 2000 B.C. in China. As little as 10 years ago falconers were taking birds from the wild to train.