With little competition for small prey, opportunistic coyotes spread throughout the entire continent. In 1914, under pressure from ranchers, Congress first appropriated funds for predator control. Armed with an extremely lethal poison called Compound 1080, agents and ranchers injected the odorless and tasteless chemical into carcasses, killing any animal, including coyotes, that ate the meat. The compound was banned in the United States in 1972 because of several accidental human deaths, along with the threat it posed to endangered species such as the bald eagle. A steel leg hold trap used to hunt coyotes.
Coyotes now thrive in every North American habitat, including cities and suburban neighborhoods.
Bob Crabtree, a Yellowstone biologist who has been studying coyote behavior for 14 years, believes that the random killing of coyotes, along with decreased competition from larger predators such as bears and mountain lions, has contributed to an extreme population boom. Trappers like Spencer are legally required to post signs warning of lethal compounds or traps in the area. Nature abhors a vacuum, and coyotes are living proof. While outright killing can temporarily reduce the population, other coyotes will soon fill the gap by shifting their territorial boundaries. Additionally, when a pack member dies, females begin reproducing at younger ages and giving birth to larger and healthier litters.