THREATS TO BIRDS OF PREY

Hunting
Millions of diurnal birds of prey have been shot over the past 150 years. As a group, they have been persecuted for killing livestock, poultry, and game birds. In truth, only a few of the larger species occasionally feed on domestic animals. Some species, like the California condor, were shot for their feathers, or just for sport.
Habitat destruction
Deforestation and other habitat destruction is currently the most serious threat to diurnal birds of prey. Habitat loss not only affects birds in their breeding areas, but also in their wintering areas.
Pollution
Diurnal birds of prey, like all carnivores, are especially vulnerable to pesticides, insecticides, and other human made toxic chemicals.
As chemicals are passed up the food chain from plant to plant-eater, and from plant-eater to meat-eater, they become more and more concentrated in the tissues of each succeeding animal. This process is called bioaccumulation.
Organochlorines, such as DDT, PCB, and dieldrin are extremely harmful in concentrated amounts. A build up of organochlorines may cause death in adults and embryos, lead to chronic illness, or cause the thinning and premature breakage of egg shells. Though several organochlorines have been banned in the United States, including DDT in 1972, they're still used in other parts of the world.
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.
Poisoning
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.
Diurnal birds of prey may also be killed by eating poison-laced carcasses set by ranchers for coyotes, wolves, jackals, or other animals considered pests. Some carcasses are set deliberately for diurnal birds of prey.
Human structures and disturbance
Accidental deaths occur when birds collide with human made structures such as buildings, fences and power lines. Power line electrocution is frequent in larger birds, like vultures and eagles, whose wings can touch two wires at once.
Many carrion-eating birds are struck by cars while feeding on or near roads.
The practice of removing or burning dead livestock (to reduce the risk of disease) has inadvertently reduced the food supply of many scavengers, such as Old World vultures.
Diurnal birds of prey may abandon territories or nest sites if disturbed by human activity.