The American black vulture, turkey vulture, lesser yellow-headed vulture, and greater yellow-headed vulture are listed as species of Least Concern by the IUCN Red List. This means that populations appear to remain stable, and they have not reached the threshold of inclusion as a threatened species, which requires a decline of more than 30 percent in ten years or three generations. The king vulture is also listed as Least Concern, although there is evidence of a decline in the population.BirdLife International (2001)
